Reversed tub overflow assembly?

I am helping a friend replace a tub drain. We are doing other work in the bathroom and opted to just remove the tub to make it easier to get the old drain off. When we got it out I saw that the overflow assembly is 'reversed' from the normal installation. The overflow arm drops to a 90 degree angle and meets the drain with a T, with the tailpiece droping straight from the drain into the trap assembly. Can I buy this type of assemply anywhere or will I need to make one from a normal assembly and other PVC parts? It does not look like I can reposition the trap to accomodate the normal overflow configuration without removing 80% of a floor joist at that point. Do you anticipate other problems with connecting the modified overflow? I imagine I will need to cut an access panel in the wet wall (it backs to a closet) to reach the nuts. Thanks.

Put 'er back the same way!

Sounds like the drain was assembled this way to get out of the joist situation, which lets face it... sometimes you just have to do. This is a modification of the drain parts to make it work, and although not ideal, I'm sure it's been working alright. I would redo the drain configuration the best way you could, we just want to make sure that we are definitely draining and venting unhindered. I hope I don't get a verbal lashing from the others for condoning this! I have been in the same situation and have had to take the same measure, as there was absolutely no possibility of relocating that joist!
You will need an access panel to make the pipe connections once the tub is in its place.

W & O

If I read the situation properly, You could order a W & O assembly out that would cover that situation......