Found this on another thread.
Changing soft keys on landscape mode in TF3D
1. Go to the HKEY_LOCAL_MACHINE\Software\HTC\\Manila key in your registry
2. If you don't have a String entry called LandscapeMenuLSKPath, add it.
3. Edit LandscapeMenuLSKPath to the program you want the left soft key to run (e.g. \windows\operal.exe)
4. If you don't have a String entry called LandscapeMenuLSKText, add it.
5. Edit LandscapeMenuLSKText to the label you want to use for the left soft key (e.g. Internet)
6. Repeat steps 2-5 for the right soft key (LandscapeMenuRSKPath and LandscapeMenuRSKText)
Remap Manila Portrait softkeys:
HKLM/Software/HTC/manila/
HomeLSKPath, which is the left softkey (Standard = Phonepad)
And
HomeRSKPath, which is the right softkey.
If you change these with the location of the programs you want to link to, and simultaneous change the names:
HomeLSKText = Left softkey text
And
HomeRSKText = Right softkey text.
(If u want the original delete both text of right softkey)
Remap Windows today softkeys:
HKLM/Software/Microsoft/Today/Keys/112 (left Softkey)
HKLM/Software/Microsoft/Today/Keys/113 (right Softkey)