Self signed certificate, https and vpn

I have access to an SBS 2011 server that has a self signed certificate.

In my computer (win 7 pro) that is outside the domain, I have imported the root certificate and the leaf certificate into windows certmgr, the leaf certificate I got from Firefox when I tried the same site (the remote web access to SBS, it uses https) then in Chrome I can't connect at all, just get a NET::ERR_CERT_INVALID error.

I also have problems connecting to their VPN, if I put up a normal PPTP connection, then that does not work at all (I think their Router doesn't allow GRE through) but when using SSTP I get a certificate error 0x80096004 "The signature of the certificate cannot be verified".

I thought that when I had imported the root certificate into certmgr then everything should work fine.

I can access the remote web through Firefox, but only after I imported those certificate in Firefox, I thought the browsers used the certificates in certmgr.

EDIT 1:

If I open up mmc and insert the certificate snap-in, and there I view the Other People folder (or catagory or whatever you want to call it) then I see no certificates. But if I open up certmgr.msc and look in Other People I see two certificates. Why is that? Should it not be the same?