I just use the PITCH switch. It can sometimes be a little slow to respond, but it does respond.

Note. Both the 2D and VC switches are synchronised, so either of them works.

EDIT: Another trick that I often use is to press the HEIGHT (it's the Altitude Hold mode), then press CTRL+SHIFT+Z, then use the keyboard + and - keys to increse/decrease the HEIGHT altitude (you need to have Cockpit Tooltips enabled to see the altitude you want to set it to), then it will climb/descend at 1800 feet per minute.