X.509 certificates authetication in SUP 2.2 SP04

Hi All,

We are building a custom SAPUI5/online/Odata/PhoneGap.SUP 2.2 mobile application for the client.We already have basic authetication and SSO using logon tickets(they have to put in username and password) configured for client. But due to password changes in SAP Gayeway backend in 180 days , user has to change the password on app after 180 days. Client want to setup X.509 certificate so that user is authenticated using this certificate in the backend.I am newbie to the whole X.509 concept and implementation, how can I achieve this in my current infrastructure of SUP2.2/SAPUI5/Odata/PhoneGap/Afaria.

Regards

Nidhideep