Create field definition with a type equal to Lookup (Count Related)

Question

Reading over this link I've decided I want to add this to a feature package I'm building. The feature is only deploying site columns and content types. My question is what should the XML look like to accomplish defining this field definition within my feature package?

Here's another link that describes this functionality. It also provides an example console app that will retrieve this information.
http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spfieldlookup.countrelated.aspx

Answer 1

Tried Aggregation="Count" or ShowField="Counter" ?

Answer 2

<Field Name="NumComments" ReadOnly="TRUE" Type="Lookup" DisplayName="Comments" CountRelated="TRUE" List="List/ListName" ShowField="PostTitle" ID="{guid goes here}" StaticName="NumComments"/>

This is what I have found that works.

Answer 3

Unfortunately I can't open that link from here as the page never opens, but you could at least start with this XML:

<Field ID="{725F9AC7-6B1D-4fd5-A810-4D2673D4A5F6}" Name="UsageType" Type="Lookup" List="Lists/UsageTypes" Required="TRUE" ShowField="Title" StaticName="UsageType" DisplayName="Usage Type" />

This is an example of a lookup I use in one of my solutions. Change the ID and names accordingly!