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.