[AccessD] Query based on form AND subform

I'm trying to build a query, to gather info for a report...a certificate I am printing (this might sound familiar, because I was here a few weeks ago and went around it...but it is back). The certificate that should be printed is based on the students SSN, which is on the main form, and the Issue date, which is on the sub form. 
 
I get the query to work w/just the SSN, by having a SSN field and entering criteria, "[Forms]![frmDataEntry]![ssn]" but there could be many certs and it will print them all. So, I wanted to narrow it down to the current subform record as well. Along w/the previous criteria, I've entered, in the "Date Issued" field, "[forms]![frmDataEntry]![frmCert_Sub]![Certificate Date]" and "[forms]![frmCert_Sub]![Certificate Date]", neither of which works...it prompts me for the date.
 
Can someone please enlighten me on the method I'm missing?
 
Thank you in advance, because I just know one of you has the answer...you always do.
 
Thanks!
 
J Clark