3 mutually-exclusive suggestions
1. Switching from Sun's SSH to a truly current and regularly updated OpenSSH based on a set of packages provided by
CSW packaging home or
Blastwave.org - An OpenSolaris Community Site, I prefer the former. You can keep most, if not all, of the Sun SSH settings you have sshd_config & ssh_config, but now you have the option of newer features/settings to use and will likely have better compatibility and synchronicity with Linux-based SSH servers.
2. Depending on what you are running on the remote server side, you can set an environment as part of your command sequence, based on your target shell
ssh user@sshServer "setenv myVarName myVarValue; /usr/bin/tcsh"
3. Write a script that creates an "export file" of variables you want imported on the remote shell, copy them with SCP to a standard location. Setup your environment shell file to source the copied export file if the $SSH_CONNECTION and $SSH_CLIENT variables are set in some fashion (as specific as you'd want to get). Then SSH as normal. Obviously this works a lot better if you are using public/private key authentication to avoid the double password prompt.