reassign pac files

[mattfick]

ive been running into brick walls the past few days. ch and most other files can be reassigned quite easily in hex, but others (with the header HSPC) im having trouble with. the only work around ive found (which takes forever) is to extract all the files, and inject one by one with gui pac editor. while it does work, that method doesnt work when injecting more files than in the original. can someone shed some light as to other methods or tell me what im missing? 

greatful for any and all advice