Hi there.
I hope I will be told that I shouldn't be doing what I am doing, but I am using the SearchValueChanged for things like these. 
I did have to make a small change into the BrowseDialog source code, since the OK button wouldn't trigger the SearchValueChanged for the control that had the last focus, being this a search field. What I did was to create a text control in the BD form and I move the focus to it and then back to where it was when the OK is pressed.
This is what I do in the SearchValueChanged:
Private Sub YourBrowseDialog_SearchValueChanged(ByVal sender As Object, _
ByVal e As MicroFour.StrataFrame.UI.Windows.Forms.BrowseDialogSearchValueChangedEventArgs) _
Handles Me.SearchValueChanged
'-- check if a combo was chosen
If e.SourceSearchField.Key.Equals("YourComboValueField")
'-- Establish locals
Dim yourInteger as Integer
'-- get the value
yourInteger = CType(CType(e.SourceControl, ComboBox).SelectedValue, Integer)
'-- do whatever needed
End If
'-- check if a Text was chosen
If e.SourceSearchField.Key = "YourTextField" Then
'-- Establish locals
Dim yourText As String
'-- get your text
yourText = e.SourceControl.Text
End If
'-- and so on...
End Sub