#ENV# and jdbc string

I am trying to setup jdbc connection for my soapui project. The db server comes from a ENV variable. So, I have setup the connection string as follows:

jdbc:sqlserver://${#ENV#TESTSYSTEM}-db:1433;databaseName=flexnetdb;user=flexnetdb;password=PASS_VALUE

But it does not seem to be working. What is the right way to do this ?

Thanks.