I found this addon plugin online. It has 2 versions one for TS 4 and the other for TS 5. Both will install under TS 6 part of TS 7.6.
Note: TS plugins go in the TSX folder. To install them select the electrical plug icon in Truespace 6, locate the TrueX folder and in install the version 5 TSX as the version 4 TSX does not appear to work well for me; the geometry looks odd in 3D Exploration. I've tested and now use the Truex5.tsx for creating models for Battlezone II Combat Commander. The models are saved as X models and later converted to XSI with 3D Exploration 1.5.5.