as I know there are no "standard" exports in firewalls to exchange configs between different products. As you've already looked for the cf command,
i would suggest you export everything that is needed like IP's, Services and so on out of your Sidewinder using ascii files, and then convert this files
to your needs, to import them again within other firewall products.
In the past I've heard from Securecomputing employees that some of their consultans have written scripts on their own, but mostly to migrate to sidewinder
firewalls from other vendors.
Hope that helps