diff --git a/base/src/org/compiere/acct/Doc.java b/base/src/org/compiere/acct/Doc.java
index 77c3733600..ac09f2c4b7 100644
--- a/base/src/org/compiere/acct/Doc.java
+++ b/base/src/org/compiere/acct/Doc.java
@@ -574,6 +574,7 @@ public abstract class Doc
 
 		//  for all Accounting Schema
 		boolean OK = true;
+		getPO().setDoc(this);
 		try
 		{
 			for (int i = 0; OK && i < m_ass.length; i++)
@@ -619,8 +620,7 @@ public abstract class Doc
 
 		String validatorMsg = null;
 		// Call validator on before post
-		if (!p_Status.equals(STATUS_Error)) {
-			getPO().setDoc(this);
+		if (!p_Status.equals(STATUS_Error)) {			
 			validatorMsg = ModelValidationEngine.get().fireDocValidate(getPO(), ModelValidator.TIMING_BEFORE_POST);
 			if (validatorMsg != null) {
 				p_Status = STATUS_Error;
@@ -723,6 +723,14 @@ public abstract class Doc
 		ArrayList<Fact> facts = createFacts (m_ass[index]);
 		if (facts == null)
 			return STATUS_Error;
+		
+		// call modelValidator
+		String validatorMsg = ModelValidationEngine.get().fireFactsValidate(m_ass[index], facts, getPO());
+		if (validatorMsg != null) {
+			p_Error = validatorMsg;
+			return STATUS_Error;
+		}
+		
 		for (int f = 0; f < facts.size(); f++)
 		{
 			Fact fact = facts.get(f);
diff --git a/base/src/org/compiere/model/FactsValidator.java b/base/src/org/compiere/model/FactsValidator.java
new file mode 100644
index 0000000000..a3484d22fc
--- /dev/null
+++ b/base/src/org/compiere/model/FactsValidator.java
@@ -0,0 +1,23 @@
+package org.compiere.model;
+
+import java.util.List;
+
+import org.compiere.acct.Fact;
+
+public interface FactsValidator {
+	
+	/**
+	 * 	Get Client to be monitored
+	 *	@return AD_Client_ID
+	 */
+	public int getAD_Client_ID();
+	
+	/**
+	 * 
+	 * @param facts
+	 * @param po
+	 * @return error message or null - 
+     * if not null, the pocument will be marked as Invalid.
+	 */
+	public String factsValidate(MAcctSchema schema, List<Fact> facts, PO po);
+}
diff --git a/base/src/org/compiere/model/PreferenceListener.java b/base/src/org/compiere/model/PreferenceListener.java
new file mode 100644
index 0000000000..19fb5ce919
--- /dev/null
+++ b/base/src/org/compiere/model/PreferenceListener.java
@@ -0,0 +1,12 @@
+package org.compiere.model;
+
+import java.util.Properties;
+
+public interface PreferenceListener {
+
+	/**
+	 * @param properties
+	 */
+	public void afterLoadPreferences(Properties properties);
+	
+}