The Legacy Edition of Santana's 1999 multi-platinum album, "Supernatural" is being released on February 16th, 2010 and is available for pre-order on amazon.com. The reissue commemorates the 10th anniversary of the original release.
The album features "Love of my Life" with Dave Matthews, but the Legacy Edition will have previously unissued "Rain Down on Me" which Dave & Carter recorded with Santana.
The song title "Rain Down on Me" refers to was was later called "John The Revelator" aka "JTR" which DMB and Santana had played live at a few shows during the 1999 tour.
You can find a couple taper versions of "Rain Down on Me" here on dbtp.org.