Contact Target CS - they should be able to help. Failing that write a letter to the Target Card Center (not the payment center) requesting that they also report to Ex (they may be but it is not processing right).
Don't feel too bad - I have a 1+ y.o. Exxon card that isn't reporting at all -- can't wait unitl it does because I'll get a nice score jump ... and neither is my Citgo card or BestBuyMC...
