Yes, you can run XLR > RCA on the sbm-1. I run XLR out of my PSP-2 into the RCA in's on my sbm-1.
You'll either have to buy some custom XLR to RCA cables, or make them yourself. Since the XLR is balanced and the RCA is not, you would have to unbalance the cable at the RCA end. To do this, simply solder the XLR ends like you usually would on a mic cable. At the RCA ends, you are going to want to solder both the low/negative/cold (choose your term of preference) and the sheild/ground together. This means that on the RCA end, the high/positive/hot (pin 2 on XLR end) would be soldered to the tip of the RCA, while the other two pins from the XLR will be soldered together to the sleeve of the RCA.
Let me know if this just confused you.
-JB