Admin API: Authentication Provider Admin Portal Create - parameters are not propagated correctly

curl -v  -X POST "https://3scale-admin.3scale.cloudapps.api-qe.eng.rdu2.redhat.com/admin/api/account/authentication_providers.xml" -d 'access_token=<TOKEN>&kind=rhsso&name=Rhsso&system_name=rhsso&client_id=admin-portal&client_secret=4a1b4fe9-d96a-4b72-8c29-3c968de3657e&site=http%3A%2F%2Frhsso-apimqe-nossl.cloudapps.api-qe.eng.rdu2.redhat.com%2Fauth%2Frealms%2Fprovider-realm&skip_ssl_certificate_verification=True&published=True'

<authentication_provider>
  <id>3</id>
  <kind>rhsso</kind>
  <account_type>Provider</account_type>
  <name>OAuth2</name>
  <system_name>custom_c4b625534aba</system_name>
  <client_id>admin-portal</client_id>
  <client_secret>4a1b4fe9-d96a-4b72-8c29-3c968de3657e</client_secret>
  <site>http://rhsso-apimqe-nossl.cloudapps.api-qe.eng.rdu2.redhat.com/auth/realms/provider-realm</site>
  <authorize_url>http://rhsso-apimqe-nossl.cloudapps.api-qe.eng.rdu2.redhat.com/oauth/authorize?client_id=admin-portal&amp;redirect_uri=https%3A%2F%2F3scale-admin.3scale.cloudapps.api-qe.eng.rdu2.redhat.com%2Fauth%2Fcustom_c4b625534aba%2Fcallback&amp;response_type=code&amp;scope</authorize_url>
  <skip_ssl_certificate_verification>false</skip_ssl_certificate_verification>
  <automatically_approve_accounts>false</automatically_approve_accounts>
  <account_id>2</account_id>
  <username_key>login</username_key>
  <identifier_key>id</identifier_key>
  <trust_email>false</trust_email>
  <published>false</published>
  <created_at>2018-04-23T08:09:10Z</created_at>
  <updated_at>2018-04-23T08:09:10Z</updated_at>
  <callback_url>https://3scale-admin.3scale.cloudapps.api-qe.eng.rdu2.redhat.com/auth/custom_c4b625534aba/callback</callback_url>
</authentication_provider>