diff --git a/org.springframework.orm/src/main/java/org/springframework/orm/jpa/persistenceunit/DefaultPersistenceUnitManager.java b/org.springframework.orm/src/main/java/org/springframework/orm/jpa/persistenceunit/DefaultPersistenceUnitManager.java
index b845ce38e47..3ad320713ac 100644
--- a/org.springframework.orm/src/main/java/org/springframework/orm/jpa/persistenceunit/DefaultPersistenceUnitManager.java
+++ b/org.springframework.orm/src/main/java/org/springframework/orm/jpa/persistenceunit/DefaultPersistenceUnitManager.java
@@ -336,8 +336,17 @@ public class DefaultPersistenceUnitManager
 	 * @param persistenceUnitName the name of the desired persistence unit
 	 * @return the PersistenceUnitInfo in mutable form, or <code>null</code> if not available
 	 */
-	protected final PersistenceUnitInfo getPersistenceUnitInfo(String persistenceUnitName) {
-		return this.persistenceUnitInfos.get(persistenceUnitName);
+	protected final MutablePersistenceUnitInfo getPersistenceUnitInfo(String persistenceUnitName) {
+		PersistenceUnitInfo pui = this.persistenceUnitInfos.get(persistenceUnitName);
+		if (Proxy.isProxyClass(pui.getClass())) {
+			// JPA 2.0 PersistenceUnitInfo decorator with a SpringPersistenceUnitInfo as target
+			Jpa2PersistenceUnitInfoDecorator dec = (Jpa2PersistenceUnitInfoDecorator) Proxy.getInvocationHandler(pui);
+			return dec.getTarget();
+		}
+		else {
+			// Must be a raw JPA 1.0 SpringPersistenceUnitInfo instance
+			return (MutablePersistenceUnitInfo) pui;
+		}
 	}
 
 	/**
@@ -420,6 +429,10 @@ public class DefaultPersistenceUnitManager
 			}
 		}
 
+		public final SpringPersistenceUnitInfo getTarget() {
+			return this.target;
+		}
+
 		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 			if (method.getName().equals("getSharedCacheMode")) {
 				return Enum.valueOf(this.sharedCacheModeEnum, this.target.getSharedCacheModeName());