What could I have missed? (SS included)

I'm currently vanquishing Joko's Domain, and have been busy looking for the last mob(s) for the past 1,5 hour. I'm about to give up, but I hope you people can help me out:

http://imageshack.us/f/163/gw010a.jpg/

Please, any tip would be welcome!

Perhaps the little rocky bit on the left side near the rez shrine. Also, iirc, any wurms you trigger MUST be killed. If you triggered some but aren't sure if you killed them then it might be worth retracting the sandy bits looking for them.

I had a few occasions where I did (or did not) gave that wurm the final blow before it dissapeared. I waited 5 secs to see if it would pop up again, but it didn't. If I didn't kill it, can i simply wait in the sandy bits till it spawns, or do i have to do something else to get him to pop-up?

EDIT: which rocky bit do you mean?

Look at the lower portal of the Bone Palace. The rocky area is below that. It looks big enough to have some foes on it, though I'm not sure if it does.

Regarding the wurms, you'll need to ride around in the sandy area until you get close enough to their spawn point. They'll pop up when you approach.

http://imageshack.us/photo/my-images/713/gw012o.jpg/

I think you mean that, nothing there. I'm gonna have to re-try the sandy areas.

EDIT: When I click the vanquishing button I get the message: "We have vanquished every foe in the area!" Yet I don't have it completed yet. Could that be the desert wurm issue?

I can't see imageshack/photobucket or similar things on the computer I am on now, but I do know that there are enemies around bone palace on the north side and sometimes on the west side on a small path connecting south and north sides.
From the rocky place you can walk around bone palace (you may have done that already, but as I said: I can't see the screenshot...). It's one of the more often missed areas as it's not clearly visible on the map.
If you have already done this, just ignore this.

Referring to this actually:

Not sure if you've seen my update but:

When I click the vanquishing button I get the message: "We have vanquished every foe in the area!" Yet I don't have it completed yet. Could that be the desert wurm issue?

Yeah, I'm pretty sure that's a wurm issue. See if there are notes about it on wiki.

Nope, nothing there. I'm afraid I'm gonna have to re-do it..

Crimpy check to see if you have the "A Deals A Deal" quest active - on the wiki page for Joko Domain at the bottom it says "If A Deal's a Deal is active, you will not receive credit for vanquishing even if the party defeats the last foe before triggering the cinematic"

Nope, I already checked that and I didn't have it active. I left the place, to bad though..