Update. tried the modified .rco files provided by cherryduck, after "reading the language tables" it powers down. so progress... but not success.
we want to uncompress the rco files from the ps3. it can work, there is no difference in file formats (rco, rco). the reason it's hard to uncompress them using psp .rco uncompressor programs is because they are designed specifically for the psp. a dev that created one of the psp uncompressors would have little trouble modifying the program to work with ps3 .rco files. it's possible that we'll have to wait until this happens for this to work.