The game is addressing "remap" files for textures bulk data, which is kind of index for respective tfc, instead of addressing tfc cache directly in usual way. I can only suggest to use some general tfc extractors to extract raw data from tfc cache and convert it. For example, there are id-daemon tools like the one from attachment, and there are also more complex tools with tfc rebuilding functionality (though they would be useless here).
Many thanks for the attachment. Had a chance to try unfortunately it outputs dds textures as 256x256 only. DC Universe Online has been going through a visual upgrade for the past few years with a large number of models sunsetted, would be nice if the newer models can be exported for posterity. It would be great if anyone could share a method for extracting the higher res textures.
P.S. the current method of quickbms tfc unpacking doesn't work any more