Custom field VM - mp3-player - playing a demo file (mp3)

[ketbel]

Hi, I'm searching for a method to play a demo file on my webshop.
I use "Shipment for Virtual Products" and the customer can buy and download products. But I want the customer could listen about 20-30 second of the mp3 file - as a demo file. Like this:



To layout the products in the frontside I use "JP CE Grid Pro" and YooTheme.

Regards
Ketil