Any and all attempts to use /ac Ascend (including the act of click-dragging the spell from your skill list into the Macro window) results in an '"Ascend" is not a valid actoion name.' error.
Several other ASTs have confirmed this issue. The problem only effects English clients, it seems.
I hope a hotfix is made for this soon, running out of hotbar space and could really do with a working Macro for Ascend.
I hear this also effects DRK's Scourge.