For IDOC in WM it will have some different configuration as in WM no output type are required for the transaction.
If you required IDOC in WM you have to configure extra setting in OMKY.
1) In OMKY under R/3 ->Ext System choose Interface Control. Select your warehose number, source type, destination type, movement type and under Receiver fill in the partner number name.
2) The IDOC generation is based on those field that mention in step 1. Only those field that fullfill the requirement will generate IDOC.
In WM not all the message type have Inbound and Outbound functions. Please refer to the link http://help.sap.com/saphelp_nw04/helpdata/en/52/16ac57543311d1891c0000e8322f96/frameset.htm
