i had a shipping experience from tehran to mumbay (India) on 2007. it isn't yor same route, but the leaving place is the same. once at the mehrabad airport in tehran, go to the cargo area offices just in front of international terminal, look for the sama rah cargo service office (just few meters after the lufthansa office) ask for mr. jafari nejad he's the chef office and try to get a deal with him. they arranged the whole shipping process for me (including bike crating and custom clearance) the amount i payed was 600$ for everything. they work with iran air the cheapest company i've found (lufthansa asked me 1200$). my personal fly ticket was 157 Eu. it took me 3 days for the whole process, then i took place on the ssame plane with my bike. hope these infos will be useful for you.
have a nice trip.