Stretching an Arch inside a Dynamic Block

Hello. This is my first Dynamic Block I've ever made. All is going well so far. I have figured out how to make it stretch and rotate. Now I am hung up on how to expand the arch upward without it detatching from the main line. A standard arch has an grip at the top of the peak to adjust this way, but once in a Dynamic block, that grip is nullefied. So in summary, I need to be able to stretch it lengthwise and stretch the arch upward. Block is attached. Any ideas?

Map Tag Block.dwg

I posted this thread on Firday. 64 people looked at it. Does anyone have any ideas?

I looked at in on Friday, looked again this morning, and the only thing I can think of to even partly replicate that action in a DB would be to use a spline. Unfortunately splines don't play too nice with stretch commands themselves so it doesn't seem to be a solution.

I was hoping there was a way to presevre the original grips of an object while still being a part of Dynamic Block.

Short of removing the arc from the DB altogether and grouping it, nothing comes to mind.

Scale Action?

I can't figure out a way to use Scale Action to make it work only in the Y direction and not the X.

AutoCAD 2010 constraints. Probably a way to do it in 2008, but I'm lazy.

What about splitting the arc into separate entities and haveing a bit more flexibility with action/parameter sets.

I'm not saying this is at all feasible, just a theory.