I ran into an interesting problem today that I was hoping you could help with.

I need to use a LOD bias on a projected texture within a fragment program. The TXP instruction looks up a projected texture, and the TXB instruction looks up a texture with bias, but there is no command to do both. Is there any way around this? I tried pre-dividing the xyz texture coordinates by w to simulate TXP, but it didn't work....why is that?