Logging raw accounting packets

I would like to put accounting logs into some sort of database, but store the entire raw binary packet as well as some decoded attributes. I can think of plenty of options for the storage: e.g. mysql Blob column, CouchDB binary attachment, MongoDB etc. But I can't see how to get at the raw packet from the freeradius config. Even rlm_perl doesn't seem to receive the raw packet, only a hash of decoded attributes. Is there a module which can do this already, or should I be looking to hack something up in C? Thanks, Brian.