AfterLogic XMail Server supports two kinds of macro declaration inside its TAB file. The old XMail macro declaration done by prefixing the macro name with the '@@' sequence, is still supported for backward compatibility, and has to be used when the macro is the only content of the parameter. Macro can also be declared as '$(MACRO)' and this form can be used anywhere inside the parameter declaration, like:
"/var/spool/mail/$(USER).dat"