diff -ur voms-clients-3.0.6.orig/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java voms-clients-3.0.6/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java
--- voms-clients-3.0.6.orig/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java	2015-01-09 14:10:14.000000000 +0100
+++ voms-clients-3.0.6/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java	2015-03-18 10:07:21.739741876 +0100
@@ -445,8 +445,12 @@
       limitProxy(proxyOptions);
 
     if (acs != null && !acs.isEmpty())
-      proxyOptions.setAttributeCertificates(acs
-        .toArray(new AttributeCertificate[acs.size()]));
+      try {
+        proxyOptions.setAttributeCertificates(acs
+          .toArray(new AttributeCertificate[acs.size()]));
+      } catch (IOException e) {
+        throw new VOMSError(e.getMessage(),e);
+      }
 
     try {