New button in configuration screen


I am developing a report plugin and I need to add a button in the report configuration window.

<report name="creation Report" i18n-name-key="" key="creation-report" class="com.jiraPlugin.jira.reports.creationReport">
    <description key="creation-report.description">The creation Report Plugin</description>
    <resource name="view" type="velocity" location="/templates/reports/creation-report/view.vm"/>
    <resource name="i18n" type="i18n" location="creationReport"/>
    <label key="creation-report.label"></label>
    <!-- the properties of this report which the user must select before running it -->
    <!-- Uncomment and edit properties... -->
        <values class="com.jiraPlugin.utility.GetSprintsForUI"/>
    <!-- -->

Does anyone know how can I add a button in this window?
The properties are very limited: long, date, project, user, select etc so I can’t add a button by using a property.

Thank you very much.