R and screen (UNIX question)

I'm having a mixed experience with using R and UNIX's screen function
-- sometimes when I close a connection that used screen, the R process
is killed (which, in theory, it shouldn't be -- it should be running
in the background).  Does anyone have any ideas on how well (or not) R
behaves with screen, and if there any tricks to using R and SOME type
of background program that doesn't require permanent connection?

--j