GetContainerAttribute - cannot find field
I am unable to return any container attributes using a calculation field in FM Pro 13. The database was converted from FM12 has a container field "Picture" but if I try the following:
GetContainerAttribute ( Picture; filename)
then I get a "The specified field cannot be found" error message and "filename" gets highlighted. I can make other calculations using container related functions but cannot get any of the attributes - general or photos related - to work. Container data is stored within the database.
If I export the photo in the container it saves with the original file name and other attributes are visible in the properties of the exported file so the data must be in there somewhere - how do I get it to appear in a calculated field?