If only I knew then what I know now, LOL.  OK so have been thinking about how to do this thing.  Went and got some heavy duty soldering stuff, and was trying to figure out how to keep things cold and hot at the same time.  Then said wait a minute, this should be something that anybody can do and do it cheaply, so scrapped the whole solder idea and did some research.  Changed tack to see how to seal the capsule without solder.  Figured that my bottle of ether came in a aluminum can with a plastic top, and a plastic seal, I needed to just make a gasket out of somwthing to seal with a screw.  Drilled and tapped the end of the brass reservoir for a 8-32 machine screw, smoothed and polished the area around the screw as best as I could.  Found out that Teflon is insoluble in ether.  Cool, got my roll of Teflon tape and took a look.  Didn't think it would seal on the threads, but might make a gasket with several layers.  Was looking for something a little thicker, then BINGO!  Teflon valve packing rope.  Perfect!!  Thought I would make a practice run, wrapped a piece tightly around a screw that I had cut down to about 1/4 inch long, and screwed it into the reservoir tight enough to deform the Teflon.  Cut off the tag ends with a razor blade and took a look.  It looked like a perfect gasket.  Why screw around, lets go for it!  Tossed the can of ether and the gauge in the freezer to cool down.  Pulled it out, filled my (just arrived from e-bay) blunt neeedle syringe with ether and filled the reservoir.  Screwed it down tight as I dared.  Let it sit for a minute or so and gave it the sniff test, could not smell any ether escaping.  Mixed up a batch of JB Weld for a final seal.  Will test it out tomorrow.  I am dying to see what will happen.  Photos are the screw and gasket, installed screw, and epoxied reservoir and blunt syringe I used to fill.  Anyway so far so good

Update:  Came back after an hour and there was a tiny bubble in the JB, did not even break the surface.  Scraped the JB off and gave it another 1/8 turn, reapplied JB.  The gauge reads a little over 100 now, where before it was bottomed out.  This is going to work!

Update 2:  Another tiny bubble, cranked it down another tiny bit, another 1/2 hour looks good!  Let er set up.

Update 3:  Dang!  Another tiny leak.  Think I know what went wrong.  Should not have preformed gasket.  Started over.  Looks good, so far.

Great work and a very interesting read... Thanks Terry

I bought the ether on e-bay.  Problem is that the smallest amount I could get was 500 ml, and that was $35, and $15 for shipping.  So payed a lot for the 15 ml or so that was actually used, but it was the challenge .  Anyway, looked at automotive starting fluid MSDS's (material safety data sheet) to see % diethyl ether and it was about 30% in the ones that I looked at, which was not enough (IMHO).   Have since found this: http://www.greenpartstore.com/John-Deere-80-percent-Premium-Ether-Starting-Fluid... MSDS says 80% diethyl ether, 10-20% lpg.  That I believe would do it.  I believe that as long as there is liquid ether in the bulb the gauge should be reasonably accurate.  The lpg/ether mix may have some impact on the boiling point but it is probably not be enough to cause problems.  For $4 a can what the heck.

So this is what I wound up needing:

Various tools to clean out the rust.
Vice (or pliers) to uncrimp the flair.
Dremel tool to cut back the wire.
5/64 and 3/32 drills to drill for the tube. ($6) 
Soldering iron and solder to reattach the tube and remove solder from end of reservoir.
Couple of drills and taps, started with 6/32 wound up with 8/32
Blunt tip 3ml syringes from e-bay. ($7)
Teflon tape ($2) and valve packing ($3) (used 3/32 but would have used 1/16 if I could get it)
JB Weld ($5)
8/32 screw
Ether ($50) but the JD 80% is $4

So there it is, should be able to do it for about $15.  I don't see any reason why this should not keep on working for a long time.  Just need to clean up and paint the bezel.