stubs in injected documents?

Hi,
is there a way to use a StubIndex to retrieve elements in injected PSI files?

Stub indexing seems to be done for the top file, only, I think.
The problem I'm trying to solve is to handle code passed to Bash's "eval" command.
I've already tried to use ILazyParseableElementType, but that didn't work as expected, beause eval takes escaped text and unescaping the next before lexing it breaks IntelliJ's PSI tree validation.

Regards,
Wallaby