Syntax for mLab MONGO_OPLOG_URL in a Windows.cmd script (& issue)

Since meteor build is failing on linux (see my other forum post), I tried running it on windows to unblock me…

BUT since the Mongo contexts must be set by environment variable only (seriously?) and they need to have an & in them for mLab, and Windows has a notorious issue with & characters in .cmd files, i have the following challenge…

rem this is in CMD.exe
set MONGO_OPLOG_URL=mongodb://,

…which fails because & is a separator in CMD.EXE

I’ve tried ^ escapes and " but they fail in other exciting ways.

Does anybody know how I can set a MONGO_OPLOG_URL with a & for windows?