Scaling walls with sprint

I got an increase with my Vampire a few days ago, and thought it would be fun to go with sprint. Now the question is, how does this work, when charging up walls?

Can you:
A. Charge 6" to the tower and then charge 6" up.
B. Still only charge 6" up the tower.

And an additional question: How would this work with Scale Sheer Surfaces?

A. Charge 12" to the tower and then 6" up, or 12" up if you have a tower that high.
B. Charge 6" to the tower and then 6" up.

Scale Sheer Surfaces mentions nothing with charges or runs, but I presume that they mean you can run/charge vertically with no reduction in speed.

Without Scale Sheer surfaces you may not charge to a building and then climb it. Nor may you move to a building and then climb it in the same turn.  You must follow the normal rules for climbing.

With Scale Sheer Surfaces you may charge up to the tower, then charge up it.

Right, sorry. I forgot to mention, that we have a house ruling about that. 
You may do this in our rules; first move to the wall, and then climb it/charge up.

Well then its kind of up to your group and your house rules then, isn't it?

Well, yes. However, the thing we were discussing were whether you still halved your movement when charging up a wall with sprint. And that's what we'd like some inputs for.

Well do you halve your movement when charging without sprint?  For example, a warrior with move 4" must be within 1" of a 3" wall if he wishes to charge someone at the top of the wall.

Aye, he must be within atleast 2" to be able to make that charge. So yes, we do. We use the rules for charging up walls, as described in the FAQ:
 
"Q: Model cannot run climbing a wall. In other FAQ question Tuomas wrote, that "You can [charge after you climbed up a wall], as otherwise buildings would be too good positions." OK, if you climb up a wall as a part of your charge move, do you count the climbed distance as "double" (just like standard when charging) or "normal" (because you cannot run when climbing a wall)?
A: Play normal while going up the wall (1" climbing = 2" charging) then double when your up there. For instance, charging a model 3" away from ledge 2" high you would use 4" of charging climbing up the wall then 3" charging the model. The model could be 1" further."

Our only addition is that you can start your charge move away from the wall.
 
An additional question; can you make a climb + a diving charge in the same round? We have a lot of buildings where you can climb up and down walls in the same turn, but when 'climbing' down, would you then be able to make a diving charge instead? It's not excactly a balcony, as mentioned in the rules, but how would you guys play with it?

Second question - only when you can see charge target when declaring charges. Ex. Through a hole in the wall you can see a model, so you declare charge->climb a wall->climb down(?)->diving charge.
Balcony is just an example. As long as distance and height are ok you can charge from anywhere. I wonder... is there any rule that disallows models standing on other models? Let's say... skaven making diving charge from a rat ogre?

What if you can 'see'/hear them with a succesful initiative test? (Which is the other way you can charge them, if you can't see through a window)
I find that our buildings are too easy to defend, if you can't make the diving charge. Especially with my Orc opponent popping "Letz Go!"

Haha, I haven't seen any disallowences, but not any allowences either!

If you can charge someone by "initiative detection" your max charge distance is 4" - not much climbing up and down I'm afraid.
How are your buildings easy defendable? How does it interact with diving charge? I understood, that Attacker needs some diving charges to counter defensive positions/bonuses/etc, right? Usually (in our games at least) it is defenders who can diving charge not attackers since they ocuppy the building with some floors.

Doesn't the rules say, that you may take an initiative test if an enemy is unseen, but within 4"? Which means he can be right on the other side of the wall.
The building I'm talking about only has a ground floor, so the diving charge would be from the top of a ruined wall

Hmmm. You got me. In fact, we always made initiative charge on same level (enemy's right after the corner). You're right, you can climb and charge. Depends of course, how wide is that wall since rules state that "most direct route shall be taken" and if going horizontaly is easier, diving charge is not an option (unless I'm mistaken again).
So you're buldings are difficult to defend from my point of view. Unless it's four walls with arrow slits, no windows and one door. That's different.

Aye  in this particular building we have a window on each side and a door, but if someone is blocking the window, I guess that I have to charge over.

Remember that:

rulebook wrote:

Models are
also considered to be in hand-to-hand combat even
when separated by a low wall or obstacle, where it is
impossible for the bases to touch physically because
the obstacle is in the way.

Yes - a low wall. We play with that as well, but this wall in particular is higher than the models