Yes but i solved it, changing everything manually with an hex editor, since i dont know well the structure of the DAT file, i use makou reactor as an "example" , i keep an unaltered version of the DAT, i modify the other with wallmarket, then i compare the two dat file and change ONLY the desired changes, with this way its works perfectly on PSP, the problem is that it very time consuming.Because you have te re insert every files one by one too.
If makou reactor could works with PSX and PSP i could finish my mod in probably 2 or 3 days, using my "manual" method tooks me 3 weeks....its now finished but ruined my patience lol, look like PSX version is unloved for modders, probably because the difficulty , one bad step and everything crashes