Using environmetn variables as value in DM variables

Hi
I need to deploy some powershell scripts using the environment variable PSModulePath, but do anyone have any idea how to set the RedGatePackageDirectoryPath variable to an OS environment variable?
Like RedGatePackageDirectoryPath=$PSModulePathMyPowershellModule
Cheers,
Anders
I need to deploy some powershell scripts using the environment variable PSModulePath, but do anyone have any idea how to set the RedGatePackageDirectoryPath variable to an OS environment variable?
Like RedGatePackageDirectoryPath=$PSModulePathMyPowershellModule
Cheers,
Anders