Z-RAM ultra 2... replacing the battery?

[Gary <dontyouspamme_vengefultacos@comcast.nospam.net>]

So, after having a fit of nostalgia, I dug my trusty //c out from storage,
and tried booting it up. In retrospect, this thing was pretty tricked out
for its day... 1MB of RAM in a Z-Ram ultra 2 card (the one with a built-in
clock... wow, remember when having a clock in a computer was a big deal?),
a 65802, and a 3.5" Unidisk. 

Anyhow, trying to boot up using my old usual boot disks resulted in the
system diving into the monitor after displaying "setting the real time
clock" which was what the system program that Applied Engineering supplied
to read the clock on the card would print on the screen. It took a while,
but I was able to find a boot disk that didn't have the clock system file
on it (I had been pretty thorough in putting it on just about any disk I
would normally boot). That disk booted up just fine, and removing the
clock.system file from the other boot disks had them boot up just fine as
well.

I'm guessing that the battery backup in this thing must be toast, and that
the battery was the only way the clock chip got power, because even warm
booting the system still gets the same message. On the plus side, the RAM
expansion function of the board seems to be working just fine.

I just disassembled the //c and removed the Z-ram board. Fortunately, the
battery didn't explode and leak noxious stuff all over the place. The
battery is pretty easy to spot on the card... a large black rectangle
labeled "VARTA Mempac 3.6V 100mAh 53010 703 012." Looking at the back of
the board, I can see that the battery seems to have four pins on it that
have been soldered into place. The pins aren't labeled on the back (in
fact, there are no traces leading away from the pins on the back... I guess
they must be on the front.) I'm hoping that the traces are labelled on the
front... or perhaps that the bottom of the battery itself is labeled.

Before I grab a soldering iron and start messing with this, I thought I'd
check to see if anyone else has managed to find a replacement for the
battery and successfully completed a transplant. I googled for Varta
batteries, and found they are still in business, but as far as I can tell,
they no longer manufacture a battery with the same specs and same form
factor as the one on the Z-Ram board. 

So, anyone replace one of these batteries before? Any tips on what to look
out for? I would like to at least get the battery off of the board, so that
there's no chance for a toxic spill should the thing decide to break open.
Getting the clock functioning again would be a nice bonus. 

I was thinking that I would perhaps just desolder the thing, and then run
leads outside of the case to an external battery enclosure... that way I
could replace the battery without opening up the much-abused //c's case
again, and could pull the battery in case I put it back into long-term
storage. I assume I can find some sort of replacement battery for this, as
long as I match the specs printed on it, right? (voltage and mAh). 

Thanks,
Gary