How to populate a query parameter list in SoapUI?

In the Request Properties, go to Multiple-Value Delimiter and set one value, lets say comma, then in the actual value you can put comma separeted the values.

In our case ids=111,222 will be transtaled to ids=111&ids=222

SoapUI currently has a known issue ("defect"?) in that it will not allow you to supply same named parameter multiple times, such as ids=111&ids=222 in your example. In their jira tracking system, it is SOAPUI-4646.

The workaround is ... not pretty.

In your endpoint, where the methods is defined, select the parameter and turn on "Disable Encoding". Then in your call, for the parameter ids, you would provide the literal value: 111&ids=222. In order to make this dynamic, you would probably have to resort to Groovy scripting.