how to add new device to existing project in wincc flex 2007

hi, guys
I add one new device to my wincc project which is integrated with s7 already. when i want to setup the new device's connection, i found there is no station and node. i try to do integration with s7 again. but i can not baceuse the "integrate to s7" is grey out.
can somebody help me? thanks lots.

You can always "Copy from STEP 7" delete it from your step 7 project and then integrate again, but that may not fix your problem with the finding of the station.