Saddly, Alt+Ctrl+Z doesn't work on the 727.

I experimented with the default Bendix-King Radio AP in the Cs727-100. You must use the controls on the CS727 autopilot. Using the Bendix-King Radio AP, you can only increase the altitude but a thousand feet with each click, so you need to activate the Alt Hold at an one thousand foot mark, like 4000, then increase it to your flight level, say 30000. You then make adjustments to the climb rate as normal to maintain the airspeed for the climb.

Summary.

Add the Bendix-King Radio AP to the 727 AP ([Window03] in the panel.cfg).
Use the controls ON THE CS727 AP!
Make altitude and VS changes on the Bendix-King Radio AP. It only does increments of 1000 feet for the altitude and the default VS is 1800, but is changeable.

Here is how I added it, in case you want to try it yourself:

[Window03]
Background_color=0,0,0
size_mm=447,233
position=2
visible=0
ident=10005
gauge00=Captain_Sim.p721.P12!P12_001_ap, 20,0, 427,106
gauge01=Cessna!Nav_GPS_Annunciator, 0,0,20,20
gauge02=Cessna!Nav GPS Switch, 0,20,20,20
gauge03=Bendix_King_Radio!Bendix-King Radio AP, 20,106,427,127

Backup the panel.cfg first!

Mark