Best bet for you is to use an after market app that does what you want, I downlaoded Clocker from the Play Store, in a summary I Love it, it does everything yo may think a Lockscreen should do, and more. Just download the free App, if you like it then you can buy the Pro version that add even more useful features.
I must admit that I'm one the smartphone users that doesn't pay for apps, for me to an app must be something extraordinary or is a must for me, I think that in 4+ years with Android I've purchased 2apps including this one, that tells you how much I like it.
The developer is an XDA member, as far as I know the only thread is the one he created when was developing the app, take a look here.