Does the AutoCompleteExtender ServiceMethod have to be a Shared function?

I need to access the value of a radio button list control to dictate the data being return back from sql statement.

I learned that I cannot access my radiobuttonlist control from the AutoCompleteExtender method because the function is shared.

Is there another way NOT to use a Public Shared Function when calling the ServiceMethod within the AutoCompleteExtender?

Thanks in advance