After temporarily moving the pivot point (Alt+Middle Mouse Click on the center of the translate tool), you can switch to scale. However, the object still scales from it's original (permanent) pivot point.
The users in the Additional Info URL were asking for the ability to move the pivot point around for the purpose of scaling Static Meshes on the fly.
Another bug that's related and seems pretty crucial to this functionality is [Link Removed]
1. Create a new Third Person Project
2. Select a Static Mesh in the default map
3. With the translate tool enabled, hold Alt and MMB Click on the white sphere in the center of the tool
4. Move the Pivot point to a new location
5. Switch to the Scale tool
6. Attempt to scale the object
Result: Object still scales relative to the original pivot point and not the temporary pivot point that you've created.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-12176 in the post.