issue with = in path

[mhainfarecom]

Hi

When I try to put a file like this:
c:\Go\addons\bin\gof3r.exe put -b prod-glad -k "xrate-csv/year=2016/test.txt" -p c:\test.txt --endpoint s3-eu-west-1.amazonaws.com
command doesn't work and fail with:
gof3r error: 403: "The request signature we calculated does not match the signature you provided. Check your key and signing method."

but when = is replaced with _:
c:\Go\addons\bin\gof3r.exe put -b prod-glad -k "xrate-csv/year_2016/test.txt" -p c:\test.txt --endpoint s3-eu-west-1.amazonaws.com
it works.

Can you tell me how should I escape = to make it work?

Best

Mikolaj