Check out http://www.mmus.us/forum//showthread.php?t=9948 .

I haven't tested it out myself as yet. But I believe you need MpkgBox (which is pre-installed in the Freedom Features Update firmware)
Opera/9.60 (J2ME/MIDP; Opera Mini/4.2.14912/504; U; en) Presto/2.2.0