Finding Payment Due Date

I want to locate the Payment Due Date on credit card invoices (pdf's).
I've been successful by using approaches like the first occurrence of the date. In this case I used "Contains Match", built the pattern using custom dates and selecting the pattern match to be the first in the document. However there are occasions where the due date does not appear as the first item and so the first date found is the invoice closing date.
To overcome this I tried making using a combination of finding content and pattern matching by creating a match that uses "Contains match" and then
"Payment Due Date (anything token)(month token)(anything token)(day token)(anything token)(year token)
But it appears that will not work. I'm assuming you can't add 'search text' to pattern matching?
Is there any way to pinpoint a specific date in a document other than counting from the beginning or the end of the document. Note also that for invoices where the Payment Due Date is omitted if no payment is due then the numerical order of the remaining dates changes so I think its likely that specifying the numerical order number of a date will not work unless you can guarantee that the content of the invoice never changes.
Any thoughts would be much appreciated.
Thanks.
I've been successful by using approaches like the first occurrence of the date. In this case I used "Contains Match", built the pattern using custom dates and selecting the pattern match to be the first in the document. However there are occasions where the due date does not appear as the first item and so the first date found is the invoice closing date.
To overcome this I tried making using a combination of finding content and pattern matching by creating a match that uses "Contains match" and then
"Payment Due Date (anything token)(month token)(anything token)(day token)(anything token)(year token)
But it appears that will not work. I'm assuming you can't add 'search text' to pattern matching?
Is there any way to pinpoint a specific date in a document other than counting from the beginning or the end of the document. Note also that for invoices where the Payment Due Date is omitted if no payment is due then the numerical order of the remaining dates changes so I think its likely that specifying the numerical order number of a date will not work unless you can guarantee that the content of the invoice never changes.
Any thoughts would be much appreciated.
Thanks.