You may also want to use the DisplayBrokenRuleDialog method on your form, if you want to show the broken rule in a dialog box.

>>Great stuff Bob, Thanks!
>>
>>One last thing: how do I get the message to say "A Plan is required" rather than "Plan FK is Required"?
>>
>
>OK, it looks like I need to edit the EntityRules.cs and change the EntityPropertyDisplayName. As this is generated by the Business Layer tool, I will need to set it in the Display Name property in the generator.