After reading through this thread it seems like there are a lot of different outcomes for this one so here is mine. I was able to do this solo as a 35 mage but not on the first attempt. My nova didn't hold them and after a short fight I died. Jaina and Tervosh showed up immediately afterwards, but nothing happened. It's a little tough to chat with Tervosh if I'm dead I guess, so I went and rezzed but by the time I got back, the camp was empty and all of the npc's were gone. So next I ran back to town to see Tervosh in Jaina's tower to try and pick this up again. but he gave me a strange message like "Hopefully, you didn't mind our assistance, but we could not allow Private Hendel to escape" which is how the quest should end, but there were no further messages beyond that. That seemed bizarre to me, so I abandoned the quest and ran back out to Hendel's camp and sure enough, there he was with a big yellow exclamation point over his head. However, his two guard buddies had not respawned for some reason. Without them, I gave Hendel a right, sound beating and exacted my revenge for killing me the first time. After that, the quest finished normally. I don't know if this scenario is repeatable or not, but dying once and reacquiring the quest made it very easy.

Finished this long thread last night with my 39 rogue. Here is my steps:

1. Talk to Commander Samaul in Theramore. I can't remember where he is, but he will appear as a yellow dot on the minimap.

2. Go to Sentry Point. If you head out west from Theramore, sentry point is the first tower on the left side of the road. It is the FIRST tower outside Theramore, there is no way you'll miss it. You'll have to ENTER the tower so the quest will show 'complete'. Talk to the guy with yellow question mark&nbsp (can't remember his name) and you'll get the next part.

3. Keep going west ON the road. I think it's a good 3-5 min run. Then you'll see the 2nd tower on the left side of the road. There is a small river near the tower. Across from the river, Private Hendel is standing there. A yellow dot of Hendel will appear on the minimap.

4. Talk to Hendel and PREPARE to fight. Like all missing diplomat quests, you'll fight Hendel and 2 guards, all 34-36. I got my HP smacked to half and realize there is no way I can survive this nasty fight. Rogue hates group fights! So what I did was to run across that little river to the tower where alliance guards are positioned. Only Hendel chased me (his 2 guards didn't come after me), with the help of a tower guard, I take down Hendel easily. When Hendel's HP reaches 30%, he will drop the fight and re-appear as green. Just like all previous fights in missing diplomat thread.

5. I am a little uncertain about what happened after, but I think my memory is correct. After Hendel re-appear as friendly, the quest should be updated to 'complete'. There will appear 3 people standing next to Hendel, one of who has a yellow question mark on top of his head.

6. Be aware, Hendel's guards are still in fighting mode! It will take a little longer for them to appear friendly.

7. After Hendel's guards appear friendly, I talked to the guy with yellow question mark. He is either the end of missing diplomat or he asked me to talked to another one of these 3 guys. But you should be able to finish missing diplomat thread at that spot. No more running around needed.

For a lv39, I got 7k xp from this process. Not too bad. The only problem is that I am heading west to Barrens with a pvp flag on me. :) I am on a pve server. But it was late at night and luckly no horde ambushes me. pvp flag will disappear after probably 5 min.

Private hendel has two bodyguards near him, if you start the quest with them being there they will attack you as well, so drag a mob to the guards before the quest and they will be focused on killing the monster. Then you start the quest and you'll only have to deal with 1 person. Otherwise you'll have to fight 3 level 35/36's and thats difficult for the lower level people