[GNC] How to setup a Scheduled Transaction for full current Credit Card Balance?

[Tom Route36]

I'm still adjusting to GnuCash as a former Quicken user; and I have a 
question about setting up Scheduled Transactions for my Checking 
account.  In Quicken it was fairly straightforward to create Bill 
Reminders (essentially Scheduled Transactions) in Checking for each of 
my Credit Card accounts.  And the amounts in each Reminder could be set 
to track each Credit Card balance.  Those Reminder amounts would update 
automatically as new transactions got entered into each Credit Card 
account.  That was great.  I could look at a list of Bill Reminders in 
my Checking account and see in advance how much money would be needed 
each month to pay off all the upcoming credit card bills.

In GnuCash though when I setup a Scheduled Transaction for my Checking 
account there doesn't seem to be anyway of doing that.  The Template 
Transaction requires me to enter a FIXED amount for each Credit Card 
account.  So the list of Scheduled Transactions won't really reflect my 
CURRENT Credit Card balances -- not unless I manually go and update them 
everyday.  I've looked thru the GnuCash documentation; but I don't see 
any mention anywhere about this topic.  Is there some way to have 
Scheduled Transactions automatically show the full current Credit Card 
account balances?

Tom