Hi,
Had the same problem, and knocked my head against the wall before giving in and calling support. I guess I could have saved myself a headache, as according to support, this is a feature request for MR4. Until then, you set one policy for access and the destination. If you put in more than one SSL policy, the least restrictive seems to take effect. It seems to take (no matter what source you put in the policy address) the address field for Source from the range of IP addresses set up in SSL VPN.
After talking to the gentleman from Fortinet (who talked to escalation before getting back to me), I tried a few configurations and have found a " solution" of sorts. Do the following after setting up your basic SSL VPN configuration.
Create two (or more) SSL VPN user groups. Split up your SSL VPN range into however many groups you want to configure. For example, if you had 192.168.1.10-20 set in the SSL VPN range, and you want to configure access for 2 groups, then the range could be split to x.10-15 for group a, and x.16-20 for group b. You would do this in the SSL User Group Options " Restrict tunnel IP range for this group " . Then create to address ranges, call the first ssl 10to15 and the second ssl 16to20, or whatever you want.
Create your base (i.e. bottom position) SSL Authentication policy, i.e. WAN1, Address SSL VPN Entire Original Pool to Internal, Entire Private net, action SSL VPN. The create 2 policies that you will insert in front of it, one a policy that will deny action all access to the private net (middle position), and one policy that will allow action access to the restricted group to whatever specific machines you want to allow access (top position).
In this setup, you end up with one restricted group, and a second (administrators?) unrestricted group. You can nest more allow/deny policies to tighted up as needed. Ok I know that is a bit confusing, so here' s a picture., it' s relatively simple once you get the idea. Think restriction by IP ranges, and SSL Action used once for authentication. Hope this helps.