IDoc Exception (4) Unsupported Operation from NW EP 7.0 ehp1 to ECC 6

Question

Hi fellow coders
I'm trying to send an IDoc (WPUWBW01) that I make in Java on an SAP NW EP 7.0 ehp1 SPS5 to an ECC 6.0 ehp4 SPS5.
I'm using the jar-files: jrfc.jar (external) and sapidoc70.jar (included in the PAR-file).
It works to request a transaction ID
//com.sap.mw.jco.JCO.Client.createTID()
String tid = client.createTID();
But when I try to send the IDoc (after I've done a "doc.checkSyntax()") with the send command:
//void com.sap.mw.jco.JCO.Client.send(Object arg0, String arg1)
//com.sap.mw.idoc.IDoc.Document
client.send(doc, tid);
I get the following exception:
com.sap.mw.idoc.IDoc$Exception: (4) IDOC_ERROR_UNSUPPORTED_OPERATION: Usage of SAP Java Connector IDoc Class Library is not supported in current environment.
As you can see it's not a JCo-exception but an IDoc exception, that makes me puzzled.
Some of the options are:
1. A port needs to be opened on ECC?
2. An RFC source/destination port needs to be created? In transaction SM59/SICF/WE21?
3. A module or the like needs to be activated in the ECC?
Any pointers in the right direction will be rewarded.
Thank you
/Petter

Answer 1

Has this type of Java -> IDoc communication without the JCo connector for third parties never been done before?
Any tips will be appreciated.
/Petter