You can export all of the stuff that you want to keep from your old common5.pac and put all of it into the common5 that you need.
For example, if you want to keep all your CSP's, CSS Icons, and stuff like that, just export the entire sc_selcharacter_en from your old one, and move it into the new one. It's pretty simple really, so I apologize if I made it confusing @.@
Actually you see i don't use sc_selcharacter_en because it does not work no matter what i do. Instead i have to use common5.pac which works perfectly. I think maybe it doesn't work cause i use beyondyou's modlauncher. Not sure why it does this. I even tried removing the _en at the end of it but it still doesn't work.