VHBL doesn't let you use plugins. You need either CEF or ARK to do it. I will assume you have one of these.
Create a folder in your / called "seplugins". In other words, create "seplugins" in the same folder as the folder PSP. Copy your plugins to the seplugins folder.
Place a txt called "PLUGINS.TXT" in your exploit save folder. Edit it to say this "umdemu,ms0:/seplugins/music.prx,on". You can edit the "umdemu" section to pops for psx games
Place GAME.TXT, POPS.TXT in your exploit save folder. Edit it to say "ms0:/seplugins/music.prx 1" (1 is on, 0 is off).
Vita 3G - 4GB/8GB - 2.02 TN-V