Do you need a T, or just a piece that adapts a rubber vacuum line to the plastic line (not necessarily a T needed for that). What you need is a brass piece that would have a rubber hose nipple on one end and a compression fitting for the plastic line on the other. Something similar to this (except the one I have pictured is actually a T):
If you can't find one at an autoparts store, try a hardware store.
I can't stand how imagestation resizes my pics. That pic looks sooo much nicer in its full resolution glory.