Enter the gift as two separate gifts, one as a cash gift not applied to a pledge and the other as a partial payment to the pledge.

OR
  1. From the gift (in Records or Batch), click Gift > Apply to Pledge
  2. The Payment Amount should reference the amount of the gift
  3. If applying payment to pledge for a different constituent, click Load Pledges From... and select the constituent
  4. Mark ?Pay and enter the Amount Applied
  5. Click OK
  6. Choose Create a Cash gift for the remainder and click OK
  7. Click Save and close if in Records or commit the batch