Can't set Value Field for a parameter in a Data Foundation

[bluecjh]

Hope this is the most appropriate forum

using BO XI and Business view manager against a SQL Server
2005 Database table.

I've added one table to a new Data Foundation
attempted to add a parameter on a date field
but every time i set the 'Value Field' for the parameter
(to this DateTime SQL table) and then hit
'OK' to save my settings the Value Field goes
back to (None) i.e. not set?

baffled?

any ideas.. thanks

BlueCJH