diff --git a/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/AbstractFilePayloadTransformer.java b/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/AbstractFilePayloadTransformer.java
index ccf957e7af..6997ffdde6 100644
--- a/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/AbstractFilePayloadTransformer.java
+++ b/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/AbstractFilePayloadTransformer.java
@@ -21,6 +21,7 @@ import java.io.File;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.integration.file.FileNameGenerator;
 import org.springframework.integration.message.Message;
 import org.springframework.integration.message.MessageBuilder;
 import org.springframework.integration.message.MessagingException;
@@ -56,7 +57,7 @@ public abstract class AbstractFilePayloadTransformer<T> implements Transformer {
 	        T result = this.transformFile(file);
 	        Message<?> transformedMessage = MessageBuilder.withPayload(result)
 	        		.copyHeaders(message.getHeaders())
-	        		.setHeaderIfAbsent("filename", file.getName())
+	        		.setHeaderIfAbsent(FileNameGenerator.FILENAME_PROPERTY_KEY, file.getName())
 	        		.build();
 			if (this.deleteFileAfterTransformation) {
 				if (!file.delete() && this.logger.isWarnEnabled()) {
diff --git a/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/FileToStringTransformer.java b/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/FileToStringTransformer.java
index 1c6a4a21dd..d8731be3c9 100644
--- a/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/FileToStringTransformer.java
+++ b/org.springframework.integration.file/src/main/java/org/springframework/integration/file/transformer/FileToStringTransformer.java
@@ -38,6 +38,7 @@ public class FileToStringTransformer extends AbstractFilePayloadTransformer<Stri
 	 * Set the charset name to use when copying the File to a String.
 	 */
 	public void setCharset(String charset) {
+		Assert.notNull(charset, "charset must not be null");
 		Assert.isTrue(Charset.isSupported(charset), "Charset '" + charset + "' is not supported.");
 		this.charset = Charset.forName(charset);
 	}