Custom Profile Provider giving error on LastUpdatedDate

[Guest]

I created a custom profile provider based on the example here
http://www.theserverside.net/articles/showarticle.tss?id=CreatingProfileProvider

It works ok, but when I try to get the last update date/time for the profile
using Profile.LastUpdatedDate I receive the following error.

Invalid column name 'PropertyNames'.
Invalid column name 'PropertyValuesString'.
Invalid column name 'PropertyValuesBinary'.

In the custom provider the properties and their values are no longer
serialized, they are broken down into individual fields (ProperyName,
PropertyValueString, PropertyValueBinary). So I understand that the
LastUpdatedDate is referencing database fields that no longer exist. I've
tried overriding the Provider.LastUpdatedDate property, but I'm not able to
get it working.

Any ideas of suggestions will be appreciated.

Thanks,
Phil