Advanced Document Template with images

We're using the advanced document template to create word files (ultimately pdfs) based on process data and data retrieved from a database table.

One of the "asks" is that we add multiple signature images to a document.

We're using the example construct MERGEFIELD "[#list logo as logo]".  Then we have a place holder image, and finally we close that off with MERGEFIELD "[/#list]"

All works well if we pass dynamic images in the Smart Service Data Inputs Images as "={logo: cons!ADT_Images}"  (where cons!ADT_Images is an array of documents that exist in our Appian document repository)

However if we try to add a second image list, say using  MERGEFIELD "[#list signature as logo]" or MERGEFIELD "[#list logo as signature]" or some other variant,  we don't see correct output.  

I guess what we're tying to understand is a better description of the values that we should be plugging into our a) template file "[#list <what goes here> as <what goes here>]" and b) what should be plugged into the Data Input "Images"

Has anyone done more work on this, and had some success?