diff --git a/lib/saml_idp/metadata_builder.rb b/lib/saml_idp/metadata_builder.rb
index 5d77caad..246297ed 100644
--- a/lib/saml_idp/metadata_builder.rb
+++ b/lib/saml_idp/metadata_builder.rb
@@ -152,7 +152,7 @@ def raw_algorithm
     private :raw_algorithm
 
     def x509_certificate
-      certificate = SamlIdp.config.x509_certificate.is_a?(Proc) ? SamlIdp.config.x509_certificate.call : SamlIdp.config.x509_certificate
+      certificate = configurator.x509_certificate.is_a?(Proc) ? configurator.x509_certificate.call : configurator.x509_certificate
       certificate
       .to_s
       .gsub(/-----BEGIN CERTIFICATE-----/,"")
@@ -163,7 +163,7 @@ def x509_certificate
     alias_method :public_cert, :x509_certificate
 
     def private_key
-      SamlIdp.config.secret_key
+      configurator.secret_key
     end
 
     def pv_key_password
diff --git a/spec/lib/saml_idp/metadata_builder_spec.rb b/spec/lib/saml_idp/metadata_builder_spec.rb
index 453a8d81..2b84c295 100644
--- a/spec/lib/saml_idp/metadata_builder_spec.rb
+++ b/spec/lib/saml_idp/metadata_builder_spec.rb
@@ -71,5 +71,36 @@ module SamlIdp
       subject.configurator.single_logout_service_redirect_location = 'https://example.com/saml/logout'
       expect(subject.fresh).to match('<SingleLogoutService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect" Location="https://example.com/saml/logout"/>')
     end
+
+    context 'with custom configurator' do
+      let(:certificate) {'a certificate'}
+      let(:configurator) do SamlIdp::Configurator.new.tap do |c|
+        c.secret_key = 'a private key'
+        c.x509_certificate = certificate
+        end
+      end
+      subject { described_class.new(configurator) }
+
+      describe '.private_key' do
+        it 'returns the given private_key' do
+          expect(subject.private_key).to eq(configurator.secret_key)
+        end
+      end
+
+      describe '.x509_certificate' do
+        context 'with a given certificate string' do
+          it 'returns the given certificate' do
+            expect(subject.x509_certificate).to eq('a certificate')
+          end
+        end
+
+        context 'with a given certificate proc' do
+          let(:certificate) {Proc.new { "a certificate from proc"}}
+          it 'returns the given certificate' do
+            expect(subject.x509_certificate).to eq('a certificate from proc')
+          end
+        end
+      end
+    end
   end
 end