I'm afraid you cannot compress resident modules with PowerPacker. The OS locates the residents by scanning for an ID inside the executable (RTF_MATCHWORD + ptr to self), and if compressed that ID cannot be found.
PowerPacker only supports packed libraries/devices if dos/LoadSeg is patched to decompress the compressed files on the fly. This also means that only disk based compression is supported.
To my knowledge Imploder has some level of support for "self contained" library/device crunching, but even with Imploded libraries/devices it is questionable if they'd work from within read only memory.
