data binding model for entity adaptors - please clarify what does entity adaptor "field attachment"

Subject: data binding model - what does entity adaptor attachment mean in 11g oim

Documentation says entity adaptors "populates the form field to which an entity adapter is attached". It implies the entity adaptor updates the form on which it is attached (e.g. generate/validate a value)

However mapping adaptors in the data object form of the oim 11g design console involves binding variables including return variable. There is object attachment but not field attachment other than the return variable binding which can specify an entity field.

When mapping an entity adaptor that I developed and attached to the UD_EBS_USER form of the EBS connector, I am able to bind the return variable to local fields by selecting Entity Field. This is almost consistent with documentation on form field attachment.