Updated Referencing Request Values (markdown)

Referencing-Request-Values.md

@@ -60,3 +60,25 @@ There are three types of request values:
   ```
 
   If the payload contains a key with the specified name "commits.0.commit.id", then the value of that key has priority over the dot-notation referencing.
+
+# Special cases
+If you want to pass the entire payload as JSON string to your command you can use
+```json
+{
+  "source": "entire-payload"
+}
+```
+
+for headers you can use
+```json
+{
+  "source": "entire-headers"
+}
+```
+
+and for query variables you can use
+```json
+{
+  "source": "entire-query"
+}
+```