The only way I could think of is to copy the memory card to a usb drive and then modify it using a pc to inject the roms you want. Other than that you would have to make another PKG based on the CD file in http://www.psx-place.com/threads/emulators-for-han-ps3xploit.16921
Yeah. I make a PKG that has the nightly build of RetroArch with some public domain roms that I found here. After signing the pkg and installing the PS2 Classics RAP file (This can be found with PS2Classic GUI), It'll boot up uLaunchELF and you can copy the roms from cdfs:/ROMS/NES/ to mc0:/. To...
Just thought I would share that the new retroarch for ps2 works on han. Roms have to be copied to the memory card for retroarch to load them.
admin edit:
PS2 Port News:
http://www.psx-place.com/threads/update-retroarch-ps2-preview-includes-2-cores-introducing-new-nigthly-ps2-releases.22007/