diff --git a/api/v2beta1/wms_conversion.go b/api/v2beta1/wms_conversion.go
index 70af262..0d6b26b 100644
--- a/api/v2beta1/wms_conversion.go
+++ b/api/v2beta1/wms_conversion.go
@@ -27,6 +27,7 @@ package v2beta1
 import (
 	"errors"
 	"log"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -153,6 +154,16 @@ func (src *WMS) ToV3(target *pdoknlv3.WMS) error {
 				Keys: cm.Keys,
 			})
 		}
+
+		if len(src.Spec.Service.StylingAssets.ConfigMapRefs) == 1 {
+			for _, layer := range src.Spec.Service.Layers {
+				for _, style := range layer.Styles {
+					if style.Visualization != nil && !slices.Contains(src.Spec.Service.StylingAssets.ConfigMapRefs[0].Keys, *style.Visualization) {
+						src.Spec.Service.StylingAssets.ConfigMapRefs[0].Keys = append(src.Spec.Service.StylingAssets.ConfigMapRefs[0].Keys, *style.Visualization)
+					}
+				}
+			}
+		}
 	}
 
 	dst.Spec.Service = service