NAnt - Check if process exists - nant

Question

We use NAnt to stop the service, replace the files and start it backup.
<echo message="Waiting for Service to stop."/>
<property name="stopWait" value="360" />
<call target="stopServiceWait" />
... which calls below block
<!--Waits specified number of seconds or until service is stopped.-->
<target name="stopServiceWait">
<if test="${int::parse(stopWait) > 0}">
<echo message="Stopping Service... Waiting ${stopWait} more seconds..."/>
<property name="stopWait" value="${int::parse(stopWait) - 1}" />
<property name="isStopped" value="${service::is-stopped(bf.serviceName, bf.serverName)}" />
<echo message="isStopped - ${isStopped}"/>
<if test="${isStopped == 'False'}">
<sleep seconds="1" />
<echo message="Service is still not stopped"/>
<call target="stopServiceWait" />
</if>
</if>
</target>
However after stopping the service the process often continues running for quite a few seconds, blocking the files. So we just wait some more time right now:
<!--Wait another 60 sec.-->
<echo message="Sleeping additional 60 seconds to ensure that process shuts down after stop."/>
<sleep seconds="60" />
Often long wait is not necessary and just extends outage, or sometimes it is not enough and the deployment has to be restarted.
Question:
Is there a way to check from NANT if the process with the certain name exists?