diff --git a/dh2.cpp b/dh2.cpp
index 19e60c39..98175ee2 100644
--- a/dh2.cpp
+++ b/dh2.cpp
@@ -5,6 +5,11 @@
 
 NAMESPACE_BEGIN(CryptoPP)
 
+void DH2_TestInstantiations()
+{
+	DH2 dh(*(SimpleKeyAgreementDomain*)NULL);
+}
+
 bool DH2::Agree(byte *agreedValue,
 		const byte *staticSecretKey, const byte *ephemeralSecretKey, 
 		const byte *staticOtherPublicKey, const byte *ephemeralOtherPublicKey,
diff --git a/dh2.h b/dh2.h
index a8c5fce4..af9d342d 100644
--- a/dh2.h
+++ b/dh2.h
@@ -12,11 +12,13 @@ NAMESPACE_BEGIN(CryptoPP)
 class DH2 : public AuthenticatedKeyAgreementDomain
 {
 public:
-	DH2(const SimpleKeyAgreementDomain &domain)
+	DH2(SimpleKeyAgreementDomain &domain)
 		: d1(domain), d2(domain) {}
-	DH2(const SimpleKeyAgreementDomain &staticDomain, const SimpleKeyAgreementDomain &ephemeralDomain)
+	DH2(SimpleKeyAgreementDomain &staticDomain, SimpleKeyAgreementDomain &ephemeralDomain)
 		: d1(staticDomain), d2(ephemeralDomain) {}
 
+	CryptoParameters & AccessCryptoParameters() {return d1.AccessCryptoParameters();}
+
 	unsigned int AgreedValueLength() const
 		{return d1.AgreedValueLength() + d2.AgreedValueLength();}
 
@@ -48,7 +50,7 @@ public:
 		bool validateStaticOtherPublicKey=true) const;
 
 protected:
-	const SimpleKeyAgreementDomain &d1, &d2;
+	SimpleKeyAgreementDomain &d1, &d2;
 };
 
 NAMESPACE_END