You will have to create a User Defined Field for the second state withholding. At the AMS Payroll Menu, select Payer>Payer Edit>User Defined Fields, double-click on the first blank line.  On the Edit screen select Examples.  Highlight Other State Withholding and click Select.  Click Apply and then OK.   

• Some notes about this User Defined Field: First, the W-2 or 1099 Box# field must begin with an "X", followed by the State Code for the second state withholding. In the example, we have entered "XB", which will attribute these wages to State B. 
• The Calculating Code must be set to "X". These X's indicate to the program that this field requires special handling.  
• This approach will NOT work correctly if you are printing a state income tax report or form, but will work fine for all federal forms (e.g., 941 &W-2) and payroll withholdings.