URL to use AWS RDS mariaDB instance as new Datasource

[Thunder Rabbit]

tldr: how do I  modify the vpc security group of the cluster using the ModifyDbCluster API?

 

I created a new instance of "Jaspersoft Reporting and Analytics for AWS" by running the CloudFormation Template, Including VPC configuration on http://community.jaspersoft.com/jaspersoft-aws/launch

The instance launched properly, and I was able to log in as superuser, and change the password.

I'm trying to create a new Datasource at http://IPADDRESS/jasperserver-pro/flow.html?_flowId=addDataSourceFlow, and I see the following error whenI click "test connection"

Exception occurred during AWS data source recovery: . The specified DB Instance is a member of a cluster and its vpc security group should not be modified directly. Instead, modify the vpc security group of the cluster using the ModifyDbCluster API (Service: AmazonRDS; Status Code: 400; Error Code: InvalidParameterCombination; Request ID: <snip>)

In the last field, no matter what URL I use I get the same error.  It must be something more fundamental.  How do I connect to RDS running MariaDB in an AWS VPC?

here's a screenshot:

 

http://i.imgur.com/2gdUkYn.png