Rendering SG-Write nodes with Nuke's Frame Server

Hey Community,
I’m having some issues with rendering Shots in our Shotgrid (now Flow) Pipeline:
Basically, the Toolset provides us with a write-Gizmo, which includes a Write (Write1) node and a node for a thumbnail, which we can ignore for now.

The issue is, that this Writenode seems to not create directories needed and thus, when trying to render with the frameserver, the process fails.
I now created a script, which first evaluates the folders and then opens the renderdialogue. The WriteTank-Nodes are the SG-Gizmos, which need a different way to evaluate the file path, but this works.
But when starting a background render, the log tells me “Render Error: Expecting a Nuke node type” - and I couldn’t find any solution to that, but it seems to have happened with other render managers as well…

Are you able to render files with the frameserver in your pipeline? If so, how?

Thank in advance.