Hi,
In summary, i think you're just having a problem in the calculation dates and interest rate fixing. TJ05 fixing date is actually equal to the calculation start date of your interest flows. Example;
Interest 1,000 due on 4/1/2013 has calc.start date 1/1/2013 to 3/31/2013. Interest rate to be maintained in table JBIRM should have a validity date of 1/1/2013 and TJ05 must also have a fixing date 1/1/2013 for your interst flow due on 4/1/2013. It is important that calculation dates of all payments being paid on same date should have an equal or same calculation date otherwise, your flows will b eoverlapping and you'll have a hard time editing or reversing flows.
Regards,
Chaikaru