Sending XML message to SAP APO

Hi,

Currently we send XML messages to SAP APO via SAP XI / PI as we dont know how to connect and send XML messages directly to APO.
I have created a connection to APO with a SAP Adapter and it gets enabled, so I know the connection to the APO server is working. But not sure how to send the XML messages.

Thanks for your help in advance.

Regards
Eka