AND IT WORKS!

Here is a little demo (I'm still working on it, but the fact that I got swaping hulls correctly made me happy!):
Download link
When everything will work correctly, I'll upload a source code.

Edit: shit... I faced another trouble, now with c_trace detecting the celling above the CCT. All troubles caused by the position of CCT hulls, cause I need to move crawling hull down (it's centered in MED) to match standing hull's lowest point, but when I switch to crawling hull (actually when crawling), then I need to update standing hull's positions, I do exactly the same but with positive value (for crawling hull offset from standing hull is -24, for standing hull offet from crawling hull is 24). This causes some shit for 'c_trace', even it actually looks correct (I debug from to positions of the trace via 'draw_point3d', and they are always the same, as it should be). Trace detects the celling at first when CCT only starts penetrating the hole in the wall (where CCT crawls in), then it doesn't see celling till CCT fully enters the hole. I don't know what to do with this right now. physX plugin from 3dgs_snake had very useful function called 'pX3ent_getfootposition' or something like this, I really miss that one now...

Edit2: I'm opened for ideas.

Best regards!