You don't need the "form" in TT/Maryland, you only have to enter the amount of the MD withholding again so that it can be put into the correct line on Form 502 or 505. Here's the whole process:
Enter the Maryland tax on Form MW506NRS in the federal return so that the withholding can be included in your federal itemized deductions. TT/Maryland will pick it up from there.
Federal Taxes (or Personal if H&B)
Deductions and Credits
I'll choose what I work on
Scroll down to Estimates and Other Taxes Paid
Select Other Income Taxes
Under Other Income Taxes Paid in 2016 is
Withholding not already entered on a W-2 or 1099
Enter the $$ withheld in the State box and select Maryland from the dropdown
Now, In TT/Maryland click through to the screen Take a look at Maryland credits. On that screen select Maryland Withholding on Real Estate Sales. Click Yes on the next screen and enter the withholding on the following screen.
