Let's dive a bit more into this: "How can this be entered and treated appropriately (recover taxes withheld) in ProConnect?"

You don't "recover" the tax withheld.

Here is the math:

Gross distribution minus tax withheld = net paid to the client.

To fully Roll Over requires you to put back the Entire total, or Gross. That means the amount withheld is needed as a Make Up amount from current funds on hand. You need to put back the Gross. Then, on the tax form, the amount withheld is treated the same as any withholding and any estimates = just an amount prepaid to taxes owed.

If you only return the amount you got, that is not a Full Roll Over. That is a Partial Roll Over. The amount not put back in, whether because of withholding or because you decide to keep and use some of the distribution, is the amount Taxable. Then, you compute how it is taxable per the tax form, basis, etc.