Roger,
You can do this with built-in OS X functionality. In the Keyboard & Mouse preference pane, go to Keyboard Shortcuts. Create a new shortcut (using the + button)...
Application = OmniOutliner Pro
Name = Paste With Current Style
Shortcut = Command-V
When you relaunch OmniOutliner, Command-V will be assigned to Paste With Current Style, not the standard Paste.
Hope this helps.
Dan Byler