For a while now my phone (Sony Ericsson K800i) hasn’t been registering calls that I have missed, dialled etc. It was annoying because if I had missed a call I would have no idea who had called!
Anyway, after searching around I finally came across the solution: Menu -> Settings -> New Events -> Pop-up.
Do that and you will be able to see the calls you have made/received/missed in the call list. I have no idea what exactly this feature does but it seems to work so I’m happy again.