diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryBuilder.java b/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryBuilder.java
index fb1a0e3..fa9f3fc 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryBuilder.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/CollectionQueryBuilder.java
@@ -240,7 +240,7 @@
         return JsonUtils.valueToTree(join());
     }
 
-    public String buildString() {
+    public String toJSON() {
         return JsonUtils.toJSON(join());
     }
 
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusTree.java
index e6ef5cd..eef19e4 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusTree.java
@@ -2,6 +2,7 @@
 
 import de.ids_mannheim.korap.query.PoliqarpPlusLexer;
 import de.ids_mannheim.korap.query.PoliqarpPlusParser;
+import de.ids_mannheim.korap.query.serialize.util.ResourceMapper;
 import de.ids_mannheim.korap.util.QueryException;
 import org.antlr.v4.runtime.*;
 import org.antlr.v4.runtime.tree.ParseTree;
@@ -480,6 +481,10 @@
             }
 
             if (layer.equals("base")) layer = "lemma";
+
+            // fixme: injected layer mapping:
+            layer = ResourceMapper.descriptor2policy(layer);
+
             fieldMap.put("layer", layer);
             if (foundry != null) fieldMap.put("foundry", foundry);
 
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java b/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
index 68173c3..cde7b8b 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
@@ -146,6 +146,10 @@
         return this;
     }
 
+    public QuerySerializer setQuery(String query, String ql) throws QueryException {
+        return setQuery(query, ql, "");
+    }
+
     public final String build() {
         return JsonUtils.toJSON(raw());
     }