The best way to avoid alerts on SoapConnectorThreadPool is to filter it off from the rule scope.
Go to Administration | Rules & Notifications | Manage Rules | Filter by Rule Scope = WebSphereThreadPool. Two rules will show up:
WebSphere Thread Pool Hung Threads
WebSphere Thread Pool Usage
For each of the rule, modify the Rule Scope under the Rule Definition tab:
To: WebSphereThreadPool where name not like 'SoapConnectorThreadPool'
Validate the syntax and Save the rule.