Could someone please help me identify this plant...

http://www.user.shentel.net/eddie180/FP/100_0846e.jpg

This is a viney plant in an arboretum in Northern Virginia growing
on a tree. We thought it might be mistletoe, but it had red berries.
Its rather cold here now, but the leaves on this plant are green
and the berries fully developed.

Thanks in advance