Streets & Trips 2007 vs. Pocket Streets

I never understood why Microsoft kept creating new maps with each new release of MapPoint/Streets & Trips that were incompatible with earlier versions of Pocket Streets. Now add one more data point to this sillyness. Microsoft stopped releasing Pocket Streets after the 2005 map editions. However, Streets & Trips 2007 can still create maps for Pocket Streets. The gotcha? It doesn’t seem compatible with the version I’m running on my Windows Mobile 5 devices. Ah well. I really do need to find an affordable map applications for the Pocket PC and Smartphone that works with a Bluetooth GPS. Any recommendations?