Small business forum: Split Transactions With Unknown Amounts

For the record, I use Gnucash as my accounting software. As with most accounting packages, each entry requires one or more offsetting entries (double entry accounting). I have come across something that I have never encountered before. I need to make a split transaction entry, but I don't know the actual amounts of the split.

At the end of the day, my POS system provides me with a daily summary. I get sales by category, total sales in cash and total sales in credit cards. I do not get a split of cash and credit sales at the sales category level. For example:

Daily Sales = $1000
Cash Sales = $700
Credit Sales = $300
Sales Summary:
Liquor Sales = $300
Beer Sales = $600
Food Sales = $100

My credit card sales will not be realized for 2-3 days and need to be recorded in a Accounts Receivable account. Obviously, cash would be realized immediately. In the old paper and pencil days, no problem:
CR Beer Sales = $600
CR Liquor Sales = $300
CR Food Sales = $100
DR Cash = $700
DR AR = $300
Debits = Credits and all is good ( at least I think so).

The issue I have is that as soon I try to credit Beer Sales, for example, Gnucash immediately wants to know what account(s) to debit. Actually all accounting packages I know of work this way. The issue is that I know what accounts to debit, but not how much to debit each one. I am sure there is some easy way to handle this, but I don't know what it is. Can anyone help?

Do I just assign all my credit card sales to one category, such as beer?
Do I evenly split my credit card sales across all three categories?

Oh, and before you ask, there is not a way to get my register to report cash sales versus credit sales at the category level. I already asked the POS company about this option.

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