referential integrity xsd schema file

[Paul Daly]

I have the following xml file:
http://www.dalyconsulting.com/AutomaticUpdates/AutomaticUpdates.xml

and the following xsd file:
http://www.dalyconsulting.com/AutomaticUpdates/AutomaticUpdates.xsd

I created them using Visual Studio 2005. The designer view of the xsd
file
shows the proper relation between application updates and database
updates.
(one db update version to many app update versions). However, when I
open
both the xml and xsd file in VS, VS will allow ficticious db version
numbers
in the app update's database version element.

I want it so that if there are two database update version numbers...
1.0
and 1.1... then only 1.0 or 1.1 should be permitted in the application
update's databaseversion element.

I have tried moving around the <xs:keyref to make sure it was in the
proper
scope. I've also looked into the xpaths to ensure that I'm selecting
the
correct elements. The problem I have is that although the designer
shows the
proper relationship I'm looking for (as far as I can tell), it doesn't
enforce referential integrety.

What am I doing wrong???

Thanks in advance for your help.