Property Transfer of Restful Webservice

Hi,
I am facing one issue. I have successfully done property transfer for normal web service.
But I am unable to do property transfer of a Restful web service thrugh SOAP UI.

Here is the response of my restful webservice-

<Response xmlns="http:///accountmgmt/balance/getBalance">
<GetBalanceResponseType>
<averageCost>0</averageCost>
<balances>
<balanceInfo>
<e>
<accountId>1088</accountId>
<balance>19</balance>
<balanceId>3</balanceId>
<balanceName>E-Counter</balanceName>
<balanceType>kWh</balanceType>
<paymentType>OTHER</paymentType>
<pockets/>
<precision>6</precision>
<refDateTime>2014-03-27T16:50:02.000+05:30</refDateTime>
<rolloverCounter>0</rolloverCounter>
</e>
</balanceInfo>
</balances>
</GetBalanceResponseType>
</Response>

Here I need the value of <balance> i.e 20 and i need to take it to a Custom Property value say bal.

so in target i am selecting bal as my target property.

In Source section, in Property transfer I am selecting Response and writing following line in the Source Textbox
//balance

but response coming as null.
This method is working fine for normal WS..

can anyone please help me out?