HCM Extract - How to prevent a child block with no data limiting the parent block

Summary:

Looking for advice on how to configure an HCM extract so that the parent block returns data even if a child block does not. 

Thank you

Content (required):

We have four similar HR extracts for different regions producing the same assignment type data. The extracts all have a child block for salary data. We have found that when the salary block has no data e.g. because the person has no current salary then no data is produced for that person despite the other blocks producing data.

Here is an outline of the blocks in the extract:

Person (PER_EXT_PAY_EMPLOYEES_UE)