Problem with mirrored part.

I'm modeling a skid frame with structural steel members. I mirrored the outside rail (I-beam) from one side to the other.

The problem is that I have tubes for fork lift pockets, penetrating the I-beams (not centred lengthwise), and when I mirror the beam, the extruded cut outs (referenced to the geometry of the pocket tube) get mirrored along the length, and thus don't line up with the tube.

I can't simply flip the beam around, as it has an 'outside' side.

Is there a way I can take the mirrored part and convert it into a regular part, remove it's dependency to the original part?

I've tried this with both mirroring and copying the original part, both ways put the extrusions (cut outs) in the wrong spot.

And no, I can't just centre the fork lift pockets.

49136-F.iam (LevelofDetail2).pdf

Another way to do it, would be to do the extrusion cut out, within the assembly (with the tubes suppressed). This puts the cutouts in the correct place in the assembly, but the parts (the beams) don't retain the cut out when I go to drop them into a dwg.

So is there a way to make 'assembly extrusions' apply to the parts they affect?

upload a pack and go if you still need help with this and i will show you how to do it, a little hard to explain