remove prefix "http://www.twitter.com/" from template tag?

I’ve had this plugin installed for quite a while and it’s been great. I needed a custom tag field to enter a fax number for each staff member but because that wasn’t listed as one of the available template tags I had been using the [staff-twitter] tag for that purpose. Until recently that workaround has been working fine, but I recently updated the plugin and now before each fax number the prefix “http://www.twitter.com/” appears before each of the fax numbers.

See example here: http://momsinmotion.net/staff/division-1-northern-virginia/

Is there a way to prevent this URL prefix from displaying? I already have 76 staff members entered this way so I would like to avoid re-assigning the fax number as a custom tag.

Thanks!
-Mike

https://wordpress.org/plugins/simple-staff-list/