I have several textures which I am storing in places like  C:\Program Files\Stardock\TotalGaming\Sins of a Solar Empire\mytextures\mytex.tga

is it possible to write a relative pathname that will use mytex.tga in a data file that I'm changing?

This sounds like it should be obvious, but the way soase handles pathnames is a bit odd, the default names are something like:

C:\GS\DataSource\Textures\Effects\radiationbombbuffsmall.dds

where nothing actually exists called GS, DataSource, or Effects. instead, that pathname will cause the engine to look for "radiationbombbuffsmall.dds" within C:\Program Files\Stardock\TotalGaming\Sins of a Solar Empire\Textures.

I would like to instead tell the game to look inside C:\Program Files\Stardock\TotalGaming\Sins of a Solar Empire\Mytextures.

Does anyone know a way to accomplish this?