Source and destination are deep structures.. can't seem to map the detail table

So, both my source data structure and my destination structure are very similarly built:

They both have a HEADER and BODY component. The HEADER has the standard AIF fields (MSGGUID, NS, IFNAME, IFVER).

I have defined the BODY as a deep structure composed of a Header Structure + a Detail Table. Each row in the BODY has a structure with a few header fields, then a table of detail data attached to it.

In my Structure Mappings, I've created 2 rows:

The first to map BODY-HEADER to my header structure.

The second to map BODY-DETAILS to my details table. Here, I've chosen "Indirect Mapping".

Selecting that row and navigating to "Define Field Mappings", I choose my destination table (DTL) and enter the Sub-table from my source structure.

At this point, I only have 1 action - to save the data in Ztables. I'm seeing that the header data is passed in fine. But there aren't any detail lines coming through.

Any ideas?

thanks alot.

RP.