This should be a fairly straight forward customization to the 03.630 report. You would insert a sub-report in the details C section where the sub-report uses the APTran table displaying the Acct and Sub fields. The linkage would use the report's ap03630_wk_APDocVO_RefNbr field linked to the sub-reports APTran.RefNbr field.
If you are at all familiar with Crystal Reports, this should be a 15 minute or less task. You would then place the custom report in the Usr_Rpts folder. You might actually want to give this report definition a new file name (e.g., 03630DIST) and then use the report control for 03.630 adding a new format using this new report name so that the user can print either the standard check register or the enhanced check register with account distribution.