Simple answer is that, yes, there are a few transition mechanisms designed for 6-to-4 and 4-to-6 conversion. What you're looking for is something akin to NAT64 (from Wikipedia):
NAT64 is a mechanism to allow IPv6 hosts to communicate with IPv4 servers. The NAT64 server is the endpoint for at least one IPv4 address and an IPv6 network segment of 32-bits, e.g., 64:ff9b::/96 (RFC 6052, RFC 6146). The IPv6 client embeds the IPv4 address with which it wishes to communicate using these bits, and sends its packets to the resulting address. The NAT64 server then creates a NAT-mapping between the IPv6 and the IPv4 address, allowing them to communicate
However, these mechanisms aren't really massively easy to set up. The conventional dual-stack (NAT-ed IPv4 and full IPv6) would be the better way to go because more applications than I'd like to name don't play well with IPv6-only environments.
Technically, you could do port forwarding as usual. Still, why not use IPv6 in your local network? Just make sure you have a firewall enabled on the clients or the gateway, otherwise your clients will be fully exposed. – Daniel B – 2014-07-04T21:59:14.900
If your ISP is providing IPv6 to you, then everything on your network should be getting IPv6 addresses, providing you have a compatible router. If you don't, then your first step should be to replace it. – Michael Hampton – 2014-07-06T14:19:53.057
As I see it, the NAT-Function of my router is disabled, when IPv6 for WAN is active. I am not possible to use DHCP with IPv6 addresses. So either I have to reactivate IPv4 on my WAN or replace my router, i guess. – user30137 – 2014-07-06T15:57:54.523