when print "before.field" layout in report,before field XXX how to send to report form session script

You don't send before fields. You only send details en can use before fields on fields that have been sorted, either presorted in the program script or sorted in the report.

Regards,
Klaas

If you wish to get some computed values in program scripts for use in report section like calculating running % (including before field) , you can export values /arrays in program script and import the same in report script .

Though technically u can get values in before.field , after.field will be better place to do.

As klass pointed out correctly , program script just sends details and before/after fields are just created in report scripts.