Well found Louis, very interesting. From step 6 under the "Quickstart" tab at the site it looks like compiled exes from Visual Studio can run without modification once security signed for the Symbian OS. I can think of no reason why legacy compiled B4PPC apps would not run but optimised compiled apps would not as they require CF 2.0 and only CF 1.0 is supported here. However getting set up to actually port an app to a device seems a convoluted process because of Symbian OS security/licensing -you can't just load and run it like a PPC app.
Only Smartphone apps are supported at the moment, although they state that PocketPC support is coming, so no chance of B4PPC developent on the device at the moment.