more XI 3.0-->IDoc-->R/3 - Trouble

hi,

i was trying to set up a scenario in which an idoc matmas04 is sent via XI to the receiver-R/3 instead of pure ALE/IDoc transfer.

I get the corresponding Error in the XI-Monitoring:

translated to English it says something like: Receiver Service can't be acknowledged as ALE Logical System.

As Outbound and Inbound Interfaces I use the imported MATMAS04-Idoc - I followed all the required steps in the configuration. I use Services without partner where both R/3s appear as corresponding business-services (which I set up in the SLD). Both services are labelled "receiver". The sender uses communication channel: idoc, which seems to be alright, and the receiver uses GeneratedReceiverChannel_IDoc.

on the XI in transaction idx2 the idoc-type shows up, in idx1 i declared a port for the receiving system, which is pointless i guess...

in SXMB_ADM I set the entry in configuration integration server, configuration data-idoc to XML_CONVERSION value 2...

any further ideas welcome - thanx in advance,

matthias