Trap black type in spot silver background

I know this is a month late but FYI

Spot silver usually run as the last colour so you need to have the silver above the black layer of the file.

So try this...

Top layer - Black text no stroke, set to knock out the silver.

Mid layer - Silver

Bottom layer - Duplicate the black text and add a stroke to give you the trapping.

The black will combine in the K plate