The new problem exists because the US carriers are required to only accept shipments from "known shippers". This policy was in place prior to 9-11 but was not used as a method of restricting cargo traffic. In DTW there are literly hundreds of forwarders capable of handling your freight. I suggest that you contact the air carrier you plan on using for your travel and have them suggest forwarders that they use. The other option is to ship via UPS, Airborne, Emory etc...
The reason that our friend was able to get his oven on NZ was the known shipper program is not in place with foreign flag carriers, in non US cities and when AA accepted it, it was now from a known shipper... NZ Secondly, there are no conflicts with "connecting" feight... an issue soon to be addressed