I've been an advance steel user for several years and I know that it needds to be the Advance Extend/Trim and not the straight autocad command.
I'm NOT a noviceuser...
I'm using it on ACAD 2015. Thought maybe that was the problem, so I opened it in ACAD 2014. Same problem. And AS2015 won't laod into Autocad Architecture now either.
At thsi point, after beign an AS user for several years, I'm not terribly pleased with where it's going now that it's an Autodesk product...I email and call tech support and it's a struggle to even get a response, much less resolution to a problem.