FromDevice(lo) -> ... -> ToHost(lo) issue

I am trying to build a kernel configuration which intercept packets on 
the loopback and process certain UDP packets. Other packets should just 
be send back to host for other applications to process.

My configuration is:

FromDevice(lo) -> Strip(14) -> CheckIPHeader() -> IPPrint('lo in') -> 
loClass :: Classifier(udp dst port 3070, -) -> MyElement;
loClass[1] -> IPPrint('lo out') -> Unstrip(14) -> ToHost(lo);

I am able to observe the packets on loopback, but the other applications 
with open sockets doesn't get the packets. If I uninstall my 
configuration it works as intended via loopback. Any help would be much 
appreciated.

Bests,
Martin D