Parameters to be customized in EL expressions in UDFs

Hello.

This may be an easy question. Please share your thoughts.

While customizing UDFs in OIM, where do we get the reference inventory of Beans that are available for various objects on the page that are being customized?

For example, if we want to add an EL expression for the value of "Binding" associated to an object on the page, where do we look it up to construct that expression?

As an example, for "Apply" button -> Binding Value = #{backingBeanScope.resetPasswdReqBean.applyButton}  

This is available out of the box.

For objects whose MBean parameters are not available out of the box, how do we construct an EL expression? Where is the object library available that can be used in the expression?