diff --git a/sw/ground_segment/tmtc/messages.ml b/sw/ground_segment/tmtc/messages.ml
index 11d07a1087..e9cedcda20 100644
--- a/sw/ground_segment/tmtc/messages.ml
+++ b/sw/ground_segment/tmtc/messages.ml
@@ -57,6 +57,7 @@ let one_page = fun sender class_name (notebook:GPack.notebook) bind m ->
           let field_name =  Xml.attrib f "name" in
           let type_ = ExtXml.attrib f "type" in
           let name = Printf.sprintf "%s %s %s: " type_ field_name unit in
+          let format_ = try Some (Xml.attrib f "format") with _ -> None in
           let h = GPack.hbox ~packing:v#pack () in
           let field_label = GButton.button ~label:name ~packing:h#pack () in
 
@@ -76,7 +77,9 @@ let one_page = fun sender class_name (notebook:GPack.notebook) bind m ->
                 let i = Pprz.int_of_value x in
                 sprintf "%s (%d)" literal_values.(i) i
               with _ ->
-                alt_value (Pprz.string_of_value x)
+                match format_ with
+                | Some f -> alt_value (Pprz.formatted_string_of_value f x)
+                | _ -> alt_value (Pprz.string_of_value x)
           and display_value = fun () ->
             if notebook#page_num v#coerce = notebook#current_page then
               if l#label <> !value then l#set_text !value in
diff --git a/sw/lib/ocaml/pprz.ml b/sw/lib/ocaml/pprz.ml
index 7a86919d23..1f0f7af96a 100644
--- a/sw/lib/ocaml/pprz.ml
+++ b/sw/lib/ocaml/pprz.ml
@@ -168,10 +168,15 @@ let rec string_of_value = function
 let magic = fun x -> (Obj.magic x:('a,'b,'c) Pervasives.format)
 
 
-let formatted_string_of_value = fun format v ->
+let rec formatted_string_of_value = fun format v ->
   match v with
-      Float x -> sprintf (magic format) x
-    | v -> string_of_value v
+    | Int x -> sprintf (magic format) x
+    | Float x -> sprintf (magic format) x
+    | Int32 x -> sprintf (magic format) x
+    | Int64 x -> sprintf (magic format) x
+    | Char x -> sprintf (magic format) x
+    | String x -> sprintf (magic format) x
+    | Array a -> "|"^(String.concat separator (Array.to_list (Array.map (formatted_string_of_value format) a)))^"|"
 
 
 let sizeof = fun f ->
diff --git a/sw/lib/ocaml/pprz.mli b/sw/lib/ocaml/pprz.mli
index a0c10daf0e..6eb4657db9 100644
--- a/sw/lib/ocaml/pprz.mli
+++ b/sw/lib/ocaml/pprz.mli
@@ -63,6 +63,7 @@ val is_fixed_array_type : string -> bool
 
 val size_of_field : field -> int
 val string_of_value : value -> string
+val formatted_string_of_value : 'a -> value -> string
 val int_of_value : value -> int (* May raise Invalid_argument *)
 type type_descr = {
     format : string ;