The actual goal of this is to convert a tinycad schematic to a dxdesigner schematic. This is just the closest I've gotten to an actual solution.
According to the documentation:
Back-annotation is limited to: gate swaps, pin swaps, reference designator renumbering, decal changes (updates the PKG_TYPE property but does not support alternate decals).
You can't add parts, nets etc. which is what it sounds like you are trying to do.
Logic will do that, so you can back annotate from Layout to PADS Logic, and then translate the Logic schematic to DxD. It won't be pretty though as every connection will be made by off-page connectors; there will be no wires on the schematic.
If you have schematic standards that you need to follow you are better off creating the schematic by hand.
I spent several weeks attempting to import schematics from DxDesigner IND 5.0, including attempting to import from PCB files, and failed miserably. I ended up redrawing those schematics that I was carrying forward with Pads VX and archiving IND 5.0 for support of the older designs. Also, the conversion of my symbols and decals to the central library continues to be a nightmare.
What is IND 5.0? Is this the DOS/Unix Viewdraw project?
If so, there should be a technote on this, but you can also find a utility and instructions at
xDX Designer Yahoo! Groups look in the files area for check.zip.