Custom Merge Tags

Custom Merge Tags

In Campaigns, I am trying to use a Custom Merge Tag to put the Company Name in an email subject.  $[UD:ACCOUNTNAME|Your Firm|]$  works for  Account Contacts but not for Leads. I also tried  $[UD:COMPANYNAME|Your Firm|]$  and it didn't work.

There is a section for Custom Contact Tags, but in CRM Leads are not Contacts? Is there a solution?