Is there specific syntax for creating attribute text expressions?

I am working on creating a symbol with building an expression with the parts database attribute text displayed as well as generic text with it.  When I do so, the parts database attributes do not pull in the data.  They do however pull in the data if placed in the symbol direct (not through building expression).

Example of what I'm looking for:

[Part_manufacturer] followed by "CABLE#"

I've entered it as [Part_manufacturer] CABLE#, [Part_manufacturer]+CABLE#, [Part_manufacturer] "CABLE#"

The word CABLE always appears, but the parts database item doesn't show up.  That portion is blank.  Am I doing something wrong?