Presenting unexpected futuristic solution to client

I'm in talks with a client who is asking me to build a software solution for his company. They have a preconceived idea of the software (that I'll build for them) which is very ancient way of doing things. But I have a far advanced solution that is being adopted around the world and it will change they way they work in very awesome way.

Trouble is, I think they'll be scared away from the new ideas and reject it altogether.

Question: Have any of you ever been in to my situation? What did you do and what outcome did that bring?

Thanks in advance. Waliur