Using Appian 7.3 on Jboss 6.1. Attempting to integrate with another system that

Using Appian 7.3 on Jboss 6.1. Attempting to integrate with another system that provides a web service with a very complex data structure. I have imported the data structure into appian as a custom data type. I have a process with "Call Web Service" Integration service node. I have provided the location of the WSDL and it seems to be working fine getting the service information.
I have a different Custom Data Type defined for my application that I am using and have forms and processes to create and manage data in. Now we want to integrate this CDT with the one provided in the WSDL which is an external system data structure and is different from ours.
The problem I am having is I don't quite understand how to map data from my data structure (which is quite simple structure designed to help with Appian processes) into the complex external data structure. Is there a mapping utility or screen that I need to use to do that?
Thanks.
Sam....

OriginalPostID-90181

OriginalPostID-90181