Just to help anyone else, and probably future me, you can get the private key by changing the Ruckus Intra-Device Communication drop-down to the certificate you imported and then click the "View PEM" button. It looks like it generates an error but the private key can be copied from this. Paste into a text editor, format properly and then save. Then use OpenSSL to create a PFX.
This only works (AFAIK) if you created the CSR on the smartzone and have the crt.