Set scriptUsername and password via REST?

The scenario I have is to instantiate/create a release from a centrally-managed template, and run the release in a different folder (folderId). No problem there via REST api. However, different folders will have different user permissions, so:

I’d like to set the ‘Run automated tasks as user’ and password when I create the release.

I’m on XLR version 8.5.x

While I do see I can kludge my way through this by using another template in the target directory which holds the user pass, and doing acrobatics to get it done, is there a simpler way to do it directly via the REST api when creating the release in the first place?