Hi Rick,
Please Refer below answers of your questions:
1 - Goto F-32 give your customer details and put special gl indicator (A) under Open Item Selection Tab then proceed to clear the document.
2 - Goto SU01 give your username their then click pencil (Change) Pushbutton. Under this choose DEFAULTS tab. Below this tab you will find a field named Decimal Notation : choose your required format their (X).
3 - Use F-22 transaction to post any type of document.
Regards,
Zain Bashir.