The Help request bit:

Maybe I'm being too ambitious or just plain dim.

I'm experimenting with attaching a circuit made up from a behavioural source to a Custom Part block. This is the top level circuit.

The circuit i want to attach to the Custom Part block is:

I've looked through the documentation but I haven't been able to find or work out the correct syntax to put in the "model" box in the Custom Part block to attach my circuit to the block. So when I try to simulate the top level circuit, the V(op) pin is shown in red because it is not connected to anything inside the Custom Part block.

Is it possible to do this or am I expecting too much of the capabilities of the Custom Part block?

The Feature request bit:

If the Custom Part block won't let me do this then can we have some way to do this? Either as an extension of the Custom Part block or as a new hierarchical circuit/block creation and editing feature?