yea that my problem too but i think i found a fix. when i was working on my at-st i found that gluing change in the feet would weigh him down. my at-st would just flop over till i did that, now i cant even knock him over!
it will stand but very carefully. there was a stand that came with the project but i didn't like it. its on my to do list. right now i just wedge it in between my other metal gear kits and collectables.