I had a TAC case for a related issue some time back in case this relates to you (if you need date format in non-US format) - TAC case 683425704 "ISE Sponsor Portal lacks international date format support" and refers to known bug CSCvb49770. This relates to the final line in the Guest account ($ui_guest_account_purge_date$) output talking about account expiry date. It's hard coded to US date format. The more TAC case we can throw at this, the sooner it might be fixed.
thank you, this is still an issue, i spoke with engineering and this requires back end changes to make it happen. Please again keep complaining to http://cs.co/ise-feedback and logging cases against the defect above