Oblivion XP has this ability. That's how other mods award Oblivion XP points for stuff, usually completing quests, but it's not limited to that. It's explained under "Adding Oblivion XP Support" here - just scroll down the page a bit. The example is for a quest, but it could be anything. In a nutshell you're using runscriptline to define the number of points in a variable called interOpGainedXP. Oblivion XP takes that and processes it like any other point gain.
I'll carry the same functionality over to Skyrim XP. I have a few more things that I'd like to implement as well. Very similar to your situation: I was hoping to do it for Oblivion XP but haven't had a chance. Although some of my ideas would have been very difficult for Oblivion and that's mainly why they didn't get done. Hopefully some of this stuff will be easier with Skyrim. From what I've seen in the SKSE thread, I think it will be.
I'll carry the same functionality over to Skyrim XP. I have a few more things that I'd like to implement as well. Very similar to your situation: I was hoping to do it for Oblivion XP but haven't had a chance. Although some of my ideas would have been very difficult for Oblivion and that's mainly why they didn't get done. Hopefully some of this stuff will be easier with Skyrim. From what I've seen in the SKSE thread, I think it will be.
Yes I know about that part, but the request was more about the second part (since it's probably lost further back in the thread) i've separated it more explicitly here:
1.Be able to remotely award experience (covered as you've mentioned)
2. Be able to message exactly what the experience was for - note that I could do this easily enough with a message but a standard form would be nicer. That would also allow you to dynamically scale or even exclude any external experience that came in and have the message system still make sense.
Not complaining anyway - i'll be delighted to have it in whatever form you produce
