Custom Field as URL?

I'd like to be able to use one of the custom field options to include a link to a website, but don't see this as an option. I am currently using OSProperty 2.7.1, and want to be able to have an MLS link as part of the listing, so visitors can follow the link to the MLS listing and get more information.

Is this possible?

Hi,
New version 2.7.3 (release in this month), the text area field will be changed to text editor field. And you will be able to add link into editor easily.
Thanks
Dam