diff --git a/ba/ba3700.cpp b/ba/ba3700.cpp
index e75738273..2de3db53d 100755
--- a/ba/ba3700.cpp
+++ b/ba/ba3700.cpp
@@ -233,7 +233,7 @@ bool BA3700_application::tipo_prima_rata(TMask_field& f, KEY k)
   {
     pag->set_sheet(*shf);  
     (*rws) = shf->rows_array(); 
-    msk->field(F_NUM_RATE).set(format("%d",pag->n_rate()));
+    msk->set(F_NUM_RATE, pag->n_rate());
   }
   return TRUE;
 }