I don't think you can. At least not with just one tool and I assume you're trying to keep this all as a Fill Pattern. I wonder if a Filter could help you here...

What I would suggest, and yes, it varies from the standard (which, as an aside, must not be very well thought out if the main BIM program in America can't do it, but I digress) is to use the same fill patterns but with different colors. You could then either print the sheet in color (ideal) or carefully choose colors that print to various grey scales which, if it's reading well now, should read just as well.

I do not necessarily need to keep this as one fill pattern. In fact, I don't think that you could create as one fill pattern. It seems to me that option is after you have created the custom fill pattern for the rated tape you then need to add the light grey fill to the wall type defined as Smoke. I have tried using transparency in the wall, override graphics, dividing into parts and overriding parts, phasing. None seem to work. I am thinking one option is to create a second plan with only the smoke walls visible in the view then overlay on a sheet.

The problem is that this image was provided but no Revit model to reverse engineer how it was completed yet the client (VA) requires it to be completed this way.

In that case... make the rated pattern into a line-based detail component and draft over you walls. I wouldn't call that BIM but it's a way to get the look the VA is after.

Incidentally, I looked at the VA guidelines for this and did you notice that none of the examples they gave show the smoke pattern? They all show the standard rated walls.

Also, I got the impression from skimming that document that the specifics weren't as important as the process. If that's the case then you could make an argument to rework their so-called standard.

There are 2 ways of doing this I think:

1. Basic Wall with black fill, apply linebased detail components with the proper grey fill arrayed along the line. Should be doable with some nifty formulas and visibility checks.
2. Custom curtain wall.
Create a curtain wall panel with the same material applied for black solid fill. Now nest in the detail component inside the panel and make it show "only when instance is cut".
Create a CW type with no mullions applied and no panel division applied (just one big happy panel sort of speak). Now apply your custom smoke screen panel and you're done.

I would personally go for the second option. More work to control, kind of a PITA to schedule (since you need a separate schedule for this) BUT it will be correct in ALL views (which is kinda important too)