Autocompletebox using a searchtable

How do I configure an AutoCompleteBox so that it looks for data (Task URL) in a search table? If I use the search-function in the rest-interface it returns data correctly. But I can't make it work in a workflow/AutoCompleteBox.

To me it looks as if there's something wrong in the syntax when using the AutoCompleteBox.

Ex:

AutoCompleteBox:

GET /Geocortex/Essentials/REST/sites/Test_RKO/searchtables/Vejnavn_postnr/query?returnGeometry=false&spatialRel=esriSpatialRelIntersects&where=Vejnavn_postnr+Like+'ing'&outFields=Vejnavn_postnr&f=json& HTTP/1.1

Rest-interface search:

.......Geocortex/Essentials/REST/sites/Test_RKO/searchtables/Vejnavn_postnr/search?Vejnavn_postnr=Ingr&f=json#

The search table is preconfigured using wildcards (%)