I am getting lost in routers and need some of the expert help so ably demonstrated here (is that creeping enough?)..

I have a server on my home network that I can happily access through http://192.168.0.17:12078/tags and similar queries. I would like to be able to access it from further afield through my router. I can set up port forwarding from my WAN IP address port 7777(say) to 192.168.0.17 but I don't know how to forward it to port 12078 in particular. Can anyone give me some pointers if this is possible? Hopefully, I have made sense so far!? (I did optimistically try http://myrouterip:7777:12078/tags but, not surprisingly, no joy)

My router is a Netgear DG824M if that makes any difference?

Any pointers you can give gratefully received...

Thanks

Nick