Have a look here for troubleshooting: searchnetworking.techtarget.com.au/articles/41635-How-to-fix-Android-Wi-Fi-problems
It should be possible to install certificates under Settings/Security and Location(dunno the exakt term,it's all in German on my phone
), if it's on your SD Card.
If however it fails, try realmb.com/droidCert
I think it's pretty much the same thing though.
//edit: somehow, it's something different...I couldn't really figure out what this is all about, 'gonna read more stuff next couple of weeks...
If you got another format, you can use this website sslshopper.com/ssl-converter.html to convert your certificate. Or just google OpenSSL convert ...something like that.
I haven't tested it, so I can't say if it works in the end, but I might find out on Thursday...Or next semester because that's gonna be the last day for the next 10 weeks I'm gonna be at uni
Try the http/s thing out yourself, I can't post links, because I'm a new user-.-