Because a colon is used for one of the variables (a windows path), a pipe (|) is used as the delimiter.
The general format for a VSS SCM Url is
scm:vss|path_to_repository|/module_name
The third variable is the path to the Visual Source Safe repository (where srcsafe.ini resides).
Note that a forward slash is necessary before the module name in the final variable.
scm:vss|C:\Program Files\Microsoft Visual Studio\VSS|/SomeProject