You can add a new field which can add unbounded operations as displayed in the image attached through the below code segment. Hope this helps.

<table name="WebServiceOperations" columns="3" maxoccurs="unbounded">
<subheading>
<heading>Name</heading>
<heading>Description</heading>
<heading>XML</heading>
</subheading>
<field type="text">
<name label="Name">name</name>
</field>
<field type="text-area">
<name label="Description">description</name>
</field>
<field type="text-area">
<name label="xml">xml</name>
</field>
</table>
Note: If you want to get the exact view you have to create or update the GC extension points. For that please refer this question.