Sharevis.Query - some help required

[A Koppcon]

Hi all
I am trying to get familiar with Sharevis.Query but as documentation almost doesn't exist I am stuck with always the same...

Based on a field "CountryKey" in my form I want to restrict/filter the values in another list "Regions" of the form. In other words - if a user selects Country Key "DE" the list of Regions should only show those relevant for Country DE.

The settings for Sharevis.Query are as follows:

list=RegionCodes; select=[RegionCountryKey], [RegionCode], [RegionDescription]; Filter=[RegionCountryKey]==@[//my:CountryKey]

This doesn't work at all. I have kept the name myFields, I can have the field [CountryKey] either directly under myFields or in any subgroup - it doesn't work.

For testing I just tried

list=RegionCodes; select=[RegionCountryKey], [RegionCode], [RegionDescription]; Filter=[RegionCountryKey]=="DE"
and it immediately works.

Does anyone have a clue what I do wrong?

Thanks
Andreas