diff --git a/browser/resource.py b/browser/resource.py
index fc20f2b..037088e 100644
--- a/browser/resource.py
+++ b/browser/resource.py
@@ -59,14 +59,14 @@ renderingFactories = {
 class CustomFileWidget(FileWidget):
 
     def hasInput(self):
-        print 'hasInput', self.request.form.get(self.name)
         if not self.request.form.get(self.name):
             return False
+        return True
 
 
 class ResourceEditForm(EditForm):
 
-    @Lazy
+    @property
     def typeInterface(self):
         return IType(self.context).typeInterface
 
@@ -78,8 +78,8 @@ class ResourceEditForm(EditForm):
             omit = [f for f in typeInterface if f in IBaseResource]
             fields = FormFields(fields.omit(*omit), typeInterface)
         dataField = fields['data']
-        if IBytes.providedBy(dataField):
-            dataField.customWidget = CustomFileWidget
+        if IBytes.providedBy(dataField.field):
+            dataField.custom_widget = CustomFileWidget
         return fields
 
     def setUpWidgets(self, ignore_request=False):
diff --git a/interfaces.py b/interfaces.py
index 50d5173..db5afc9 100644
--- a/interfaces.py
+++ b/interfaces.py
@@ -608,12 +608,26 @@ class IFile(IResourceAdapter, IResourceSchema):
         may be downloaded instead.
     """
 
+    data = schema.Bytes(
+                title=_(u'Data'),
+                description=_(u'Resource raw data'),
+                default='',
+                missing_value='',
+                required=False)
+
 
 class IExternalFile(IFile):
     """ A file whose content (data attribute) is not stored in the ZODB
         but somewhere else, typically in the file system.
     """
 
+    data = schema.Bytes(
+                title=_(u'Data'),
+                description=_(u'Resource raw data'),
+                default='',
+                missing_value='',
+                required=False)
+
 
 class IImage(IResourceAdapter):
     """ A media asset that may be embedded in a (web) page as an image.
diff --git a/resource.py b/resource.py
index 141e681..a9b4857 100644
--- a/resource.py
+++ b/resource.py
@@ -323,8 +323,6 @@ class ExternalFileAdapter(FileAdapter):
         return self.context.__name__
 
     def setData(self, data):
-        if not data:
-            return
         storageParams = self.storageParams
         storageName = self.storageName
         storage = component.getUtility(IExternalStorage, name=storageName)