LOS Collision?

OK, so maybe I'm missing something here, but using Maya2DTS and custom collision meshes and for the life of me I can't seem to get the LOS collision to work ... the player collision works just fine, but crossbow bolts just go straight through that sucker ... as does the default buggy.

Now I'm no coder per se, so if there's a non-code solution to this, that would be fine, I'm following the instructions and naming conventions in Danny Ngan's Maya2DTS tut to the letter but no joy. If it has to be code, that's fine, I have a coder at my disposal if needs be ...

Thanks in advance guys ...