After a bit more experimentation, I took out silverwing and put in balanced stance to deal with warrior shout. Full bar looks like this:
Need at least 12 in Strength for 13 sec sprint. Inspiration should be 7 or more. Distribute rest accordingly. Use a zealous sword.
Sever
quivering blade - yea, I forgot the elite for some reason.
Spirit Shackles
tiger stance
balanced stance
dolyak
heal sig
sprint
It's not guaranteed, and certainly not that easy. If you want to be more certain, you'll probably want to 5 man or something. Sometimes you'll get snared and you die. But I've still been able to do it even with 30% dp. The key is to try to pull the warden group further and further back towards the mesmer boss. That way, once you sprint through, you'll get just jayne to follow you. I'll make a video once I perfect this some more. But in the meantime, see below (yes, I forgot the elite again):
Addendum: Here some more screenshots showing how this works (for those that want to try this out and cant wait for the video).
Step 1: The initial configuration of the mob. Note that I have Jayne selected. Always have her selected on your radar.
Step 2: Pull the mob back, but leave Jayne where she is. Note where Jayne is relative to the mob. Make sure she's far enough away. If not, just wait until she moves away. Eventually, there will be enough distance for you to aggro just the mob. Try not to aggro the Mesmer boss's group if you cant help it, but it's not a huge deal. If you happen to do so, immediately run forward again through the warden mob. Btw, did I meantion to keep jayne selected? :P.
Step 3: The run through. Didnt have time to take the screen shot unfortunately, but basically, the sequence is to hit balance stance and start running. When the Warden of the forests get close, they will use their shout. Then immediately hit sprint to run through. If you set off a trap, you're toast. But again, you can still do this even at 30% dp. Traps are always around the spirits, so avoid going through them. Also, note where the wardens of the branch are, and dont go near them either.
Step 4: Pulling Jayne out. Below you'll see what is optimal configuration. That is, Jayne is pulled and is the ONLY one attacking you. Why does this work? As the OP pointed out, Jayne is indeed SEPARATE from the mob, like a lot of other bosses. Also, when running through, you'll notice that at some point, the warden mob will stop chasing you and actually come to a standstill (sometimes even ball up). However, because Jayne is toward the uppper end of the radar, you'll aggro her as well, and she can be uplled much further. At this point, start moving forward a little to get Jayne in your aggro bubble, then start pulling her back to a safe location.
Step 5: Kill Kill Kill. When you think you've got her far enough away, start engaging.. Cast spirit shackles. Wait a bit, cast it again. After the second time, she'll be depleted, so move up, hit dolyak, and start whacking. Repeat until she goes down.
Hope that was more helpful. Video is coming soon since I know this sounds complicated.
6/18/06 - Added videos below. The first video shows the way it usually works. Wasn't my cleaniest run, but it got the job done.
Download xvid codec to view it http://www.xvidmovies.com/codec/
http://files.filefront.com/jayne_far.../fileinfo.html