diff --git a/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDVisualizer.java b/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDVisualizer.java
index b2e47e3c..64e14fc3 100644
--- a/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDVisualizer.java
+++ b/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDVisualizer.java
@@ -249,6 +249,12 @@ public class ZUGFeRDVisualizer {
 		EStandard theStandard = findOutStandardFromRootNode(fis);
 		fis = new FileInputStream(xmlFilename);//rewind :-(
 
+		return toFOP(fis, theStandard);
+	}
+
+	protected String toFOP(InputStream is, EStandard theStandard)
+		throws FileNotFoundException, TransformerException {
+			
 		try {
 			if (mXsltPDFTemplate == null) {
 				mXsltPDFTemplate = mFactory.newTemplates(
@@ -263,11 +269,11 @@ public class ZUGFeRDVisualizer {
 
 		//zf2 or fx
 		if (theStandard == EStandard.facturx) {
-			applyZF2XSLT(fis, iaos);
+			applyZF2XSLT(is, iaos);
 		} else if (theStandard == EStandard.ubl) {
-			applyUBL2XSLT(fis, iaos);
+			applyUBL2XSLT(is, iaos);
 		} else if (theStandard == EStandard.ubl_creditnote) {
-			applyUBLCreditNote2XSLT(fis, iaos);
+			applyUBLCreditNote2XSLT(is, iaos);
 		}