try it with 4 lines, like:
Account_Type: G/L Account, Account_No: 6124, Amount = 88, Bal. Account No. = blank
Account_Type: G/L Account, Account_No: 6280, Amount = 23, Bal. Account No. = blank
Account_Type: G/L Account, Account_No: 6137, Amount = 10, Bal. Account No. = blank
Account_Type: Vendor, Account_No: AAM00, Amount = - 111, Bal. Account No. = blank
Posting Date, Document No., is the same in all lines
External Doc.No. is only needed in the "vendor line"
you can also use a different sorting of the lines