Nonresident Duty Day Reporting

Due to statutory requirements, when employees work for a certian time period in a state other than there home state, we need to make sure that we tax them for the time worked in the other (nonresident) state. For example, if my home state is NY, but I spend a week working in OH, then we need the SAP HR Payroll system to tax for my time spent in OH. We are currently creating infotype 208 entries manually based on a report that indicates when employees have worked in another state. This process is causing issues, however, because when a retro occurs, the employee is then getting taxed for payments other than regular wages for the other state, i.e. OH. We only want to tax the employee for regular wages earned in the non-resident state, we don't want to tax them for special payments or bonues earned during that timeframe. Is there another (automated) way to handle this in SAP? How are other companies handling this? Any comments would be greatly appreciated.... thank you ....

Linda