RE: Integration Manager - Cash Receipts Applied / Unapplied
The issue is, for the Cash Apply sub-collection options, you would be specifying the rule as "Use Source Recordset" to be able to import the apply portion. When you do this, Integration Manager will be expecting records for that will be used to be applied by the Cash Receipt, even if the table relationship type is set to 0..M.
Couple things to try:
1. You could tell IM to Use Default if the Apply-To Document Number in the Cash Apply sub-collection is null. You would also need to set the 'Use Default' property for every other mapped field within that collection when the imported value is null.
2. You could effectively create two integrations, one for Cash Receipts with Apply info and one for Cash Receipts without apply info. You could then choose to create an Integration Group to run them both as one integration.