In web access portal, add a "Choose Details" for Date Modified

I'm unfamiliar with TFS, hopefully this is simple. I was asked to add a metadata column to the web interface (not Sharepoint, where I could add it through List Settings). When a user drills down to the source code, they're able to see:

Name | Pending Change | User | Version

We need to add a "Date Modified" column.

Thanks,

Scott