Adding a environment variable

Hi,

i created a bundle with a installation of a exe file and i like to add a environment variable. In the Action tab -> install i select the "Launch Executable" and there is a option "Environment Variables". I add a environment variable:

Name: Path
Value: T:\bin

i checked the setting: Add to existing data
Then i select append
and set Use Separator character to ;

But the environment variable is not set. What did i wrong? The Path variable is existing.
Greeting,
Steffen