Need help: Motors go correct direction. HOME is reversed?

Hello!

Kossel running Ramps 1.4. Marlin (for delta) In Repetier Host. My motors will move up and down via the up and down arrows under MANUAL. But if I press HOME for any of the 3 the carriages go down not up? I have mechanical switched at the top of my columns. The switch are working from previous tests.

How can I correct the Homing Direction?

Thanks

Maxi