You can set some defaults to increase SOPE compatibility with WO ...

Some new bits of information: to ensure better WO-compatibility, some user defaults need to be set:

WODirectActionRequestHandlerKey

SOPE per default uses a different request handler key for direct actions, set this default to wa to improve URL compatibility.

defaults write NSGlobalDomain WODirectActionRequestHandlerKey wa

WOComponentLoadWOOFiles

If you have .woo files (WebObjects Builder object files, contains things like EODataSources) inside your .wo wrappers, enable this option (set to YES) to make them load.

defaults write NSGlobalDomain WOComponentLoadWOOFiles YES

WOKeyPathAssociationClass

The WOKeyPathAssociation usually used in SOPE does all the key/value processing on its own. This brings some differences to regular KVC processing (eg SOPE KVC doesn't allow direct access to object ivars).
To make SOPE use the system KVC processing, set the default to WOKeyPathAssociationSystemKVC.

defaults write NSGlobalDomain \
WOKeyPathAssociationClass \
WOKeyPathAssociationSystemKVC

WOFormAlwaysPassDown

Set this option to YES if you have pages which contain multiple WOForm's. Per default SOPE calls -takeValuesFromRequest:inContext: on each object in the template (I think like WO 3.5). By enabling the mentioned default only walks into active forms.

defaults write NSGlobalDomain WOFormAlwaysPassDown YES