Send Tony at Iron Cross Audio and email or use the private message/email facility here since he participates on this forum.
From a strictly information standpoint, the HD catalog says the rear speaker pod kit won't fit the SESG2:
http://www.harley-davidson.com/gma/gma_product.jsp?PRODUCT%3C%3Eprd_id=845524448775822&FOLDER%3C%3Efolder_id=2534374302290635&ASSORTMENT%3C%3East_id=2534374302290635&bmUID=1283805808797&bmLocale=en_USHowever, if you look at the wiring diagram for the SESG2 in reply #4 in this thread, the harness has provision for rear speakers (left/right) in addition to the fairing, fairing lower, and tweeter speakers, but that harness has no provision for passenger controls as the Ultra has; just two wires for each speaker:
http://www.cvoharley.com/smf/index.php?topic=53364.0I'm
guessing you could use the non-Ultra overlay harness, p/n 70169-06 that would access the 35 wire connector (and is used for a variety of Ultra accessories on non-Ultra fairing models) and use the HD rear speaker pod kit to connect to that harness and not the rear speaker connector on the SESG2 harness. (EDIT: I deleted reference to the wiring of rear speakers on the FLTRUSE and CUSE6 because, unlike prior years, these models do NOT receive a rear speaker signal from the HK head unit via the 35 wire connector; instead, the front speaker signals are sent to the amplifier and the amplifier provides separate amplified signals to the front and rear speakers.)
As originally mentioned, contact Tony in the absence of a more definitve answer.
Carl