#301 cooperation with VSS-explorer fails

[Wimmie!!]

when using VSS-explorer for checking in/out files, with eclipse still open on the project, the VSS plugin seems to loose track of the status of the files
f.i. a file checked in by VSS-explorer cannot be checked out by the VSS plugin, and eclipse will see this file as read-only instead of checked-in
(eclipse 3.2.2, vss plugin 1.6.1)