Hmm, you did ask "How do I create a mod pack in Solder?" So I did think you ment how to make it in Technic Solder.
Anyway, what you need is a FTP server then, so you can access your files:)
Heres a documentation that help me out, good luck:)
https://help.ubuntu.com/10.04/serverguide/ftp-server.html