From Demetra Beta feedback:
"A $moduleclasspath$ option is missing from the External Tool's Macro dialog. As our main project is a large collection of modules the $CLASSPATH$ entry is too long to issue to DOS commands and also unnecessary for many command-line tools. It would be great to see this small but very useful feature implemented."
In fact, two different variables are needed: one for "design time" module classpath, another for "runtime" (with dependencies)