I think until today there are about 25 KNX installations running with Pronto and the Weinzierl IP gate. Send me a personal mail, and you will get the XCF and documentation. To my opinion this is the a better way to communicate with KNX than the two examples on the Philips professional web :

1) This 2way communication is NOT using RS232 -> you don't even need an extender.
2) You configure the "Pronto - KNX" objects as usual with your ETS software. The Gate is not writing directly on KNX gropup adresses -> the bus traffic stays absolutely transparent.