Index: openacs-4/packages/xotcl-core/tcl/bgdelivery-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/bgdelivery-procs.tcl,v
diff -u -r1.47.2.10 -r1.47.2.11
--- openacs-4/packages/xotcl-core/tcl/bgdelivery-procs.tcl	29 Jan 2015 09:24:01 -0000	1.47.2.10
+++ openacs-4/packages/xotcl-core/tcl/bgdelivery-procs.tcl	16 Mar 2015 08:57:25 -0000	1.47.2.11
@@ -620,7 +620,11 @@
       } elseif {[llength $ranges]>1} {
         ns_log warning "Multiple ranges are currently not supported, ignoring range request"
       }
-      my write_headers $status_code $mime_type $bytes
+      if {$::xo::naviserver && ![string match text/* $mime_type]} {
+        my write_headers -binary -- $status_code $mime_type $bytes
+      } else {
+        my write_headers $status_code $mime_type $bytes
+      }
     }
 
     if {$bytes == 0} {