Insert ROM in PDA file

I have a problem. I am new in the domain of android customization and that is why I am testing. I have a PDA file for my old GT-S6102 Galaxy Y, which contains the following files: - boot.img - param.lfs - Sbl.bin - system.img - userdata.img I also downloaded a custom ROM from the internet called evo_x2.1 (evo_x2.1.zip) which contains the following files: - META-INF (folder) - system (folder) - installbusybox (file) Normaly this file is supposed to be put on /sdcard and update the system partition only from recovery mode. But I have a question: Can I edit my PDA file mentioned above by inserting this ROM in it? (so that when I flash this firmware with odin into my phone I will no longer have to update it with this ROM separately afterwards, manually) I tried to create a system.img which contained the files included in the ROM file and replaced the system.img in the PDA file with the system.img I just created from the ROM file.But when I try to flash the PDA with Odin, it crashes while analyzing the file. NOTE: there is no md5 hashsum at the end of the PDA so there is no problem concerning the integrity of the file. Thank you, and any observations are welcomed.