Решением было создание пользовательской привязки:
protected override SecurityBindingElement CreateMessageSecurity()
{
SecurityBindingElement security;
security.EnableUnsecuredResponse = true;
security.IncludeTimestamp = true;
security.LocalClientSettings.TimestampValidityDuration = TimeSpan.FromMinutes(1);
security.SecurityHeaderLayout = SecurityHeaderLayout.Lax;
security.DefaultAlgorithmSuite = SecurityAlgorithmSuite.Basic256;
return security;
}