Can't Get Pipeline Name as Part of Spool Number

I have set up my I-Configure project to use Auto Pipeline Ref as the Spool Drawing Name Rule, along with a prefix of "MK-" and a numeric suffix. When I run the isos the spool numbers only have the prefix and suffix, I.E. MK-1, MK-2, MK-3 etc.

How do I get the pipeline name into the spool number?

Thanks

following.