Yay! datapower..
Why would you want to do this ?
If it really is just device level events - why not set up a new log destination off box on the default domain ?
http://www-01.ibm.com/support/docview.wss?uid=swg21269136
If you want to go via the XML interface, you're going to have to write a SOAP client to do your queries and set it up as a scripted input in splunk.