WIP. config accepts custom_field property and checks model for custom fields if it's true. not tested at all.

app/models/export_card_configuration.rb

@@ -37,7 +37,7 @@ class ExportCardConfiguration < ActiveRecord::Base
     REQUIRED_COLUMN_KEYS = []
     VALID_COLUMN_KEYS = ["has_label", "min_font_size", "max_font_size",
       "font_size", "font_style", "text_align", "minimum_lines", "render_if_empty",
-      "width", "indented"]
+      "width", "indented", "custom_field"]
 
     def assert_required_keys(hash, valid_keys, required_keys)
       hash.assert_valid_keys valid_keys

lib/open_project/pdf_export/export_card/column_element.rb

@@ -35,7 +35,17 @@ module OpenProject::PdfExport::ExportCard
 
     def draw
       # Get value from model
-      value = @work_package.send(@property_name) if @work_package.respond_to?(@property_name) else ""
+      if @config['custom_field']
+        # Get
+        vs = work_package.custom_field_values.select {|cf| cf.custom_field.name == property_name}
+        value = if vs.first && vs.first.value
+                  value vs.first.value
+                else
+                  ""
+                end
+      else
+        value = @work_package.send(@property_name) if @work_package.respond_to?(@property_name) else ""
+      end
 
       if value.is_a?(Array)
         value = value.map{|c| c.to_s }.join("\n")