Windows Phone 8.1 Edge Client Certificate Authentication

In general you can follow the Soln doc for the client cert configuration on APM end

https://support.f5.com/kb/en-us/products/big-ip_apm/manuals/product/apm-authentication-single-sign-on-11-6-0/16.print.html

As per the release notes, the feature is not there.

https://support.f5.com/kb/en-us/products/big-ip_apm/releasenotes/related/relnote-edgelclientwinphone-8-1.html

But you can test it, if you have a way to push the client cert.