We got it working nicely. The procedure was:

1. Started the I-deas interface
2. In I-deas went to the Options - Preferences - Selector panel and toggled everything on
(This was the step we didn't take at first.)
3. Toggled on the GD&T button, left Locators toggled off in interface
4. In I-deas set the filters....
The important ones for GD&T are
Feature_Ctrl_Frame
Datum_Feature_Symbol
5. Converted the part.

We would also like to thank Monika Carlson from Silma for co-operation. It seems that Silma's help desk have helpful and skilled employees.

Mika&Janek