XML API: Purchasing: How to list Posting configurations?

[Gunnar Fornes]

For purchasing and transaction definitions, how do I use the XML api for listing all posting configurations?

I see the query for listing transaction definitions, but the response doesnt include the posting configurations. How do I fetch those? 

[Gunnar Fornes]

Alternatively:

Given a Purchase Order, which has an GLGROUP, how do I go from that GLGROUP to the mapped ACCOUNTNO, using the XML api?