I have a SharePoint Search event in a K2 process that uses a filter to search for particular items in a named SharePoint list. The matching items are returned to an XML content field. The column used in the filter is of type ’Parent Drop Down List’. This is a custom column type (downloaded from http://customfieldcontrols.codeplex.com/). An example of the meta data for one of these list items is: <Prospectus_x0020_ID Title="Prospectus ID" Name="Prospectus_x0020_ID">10002</Prospectus_x0020_ID> but the filter (’Prospectus ID’ ’Equals’ "10002") does not pick this up.
If this column is of type lookup (eg of metadata&colon; <Prospectus_x0020_ID Title="Prospectus ID" Name="Prospectus_x0020_ID">5;#10002</Prospectus_x0020_ID>) then the filter works and returns results.
The process can extract the value from the parent drop down list column and successfully populate a datafield.
We have ASP.NET forms that also retrieve this data successfully (with C# code: SPQuery.Query = "<Where><Eq><FieldRef Name=’Prospectus_x0020_ID’/>" + "<Value Type=’Text’>10002</Value></Eq></Where>";)
It seems that the search event will not recognise the value in this column type.

Has anyone had experience with this type of column?  Incidentally, the search filter also doesn't seem to pick up values in site columns either.