Use this
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Header>
<SessionIdHeader xmlns="http://www.inwise.com/webservices/v2">
<SessionId>{SessionId}</SessionId>
<EndSession>false</EndSession>
</SessionIdHeader>
</soap:Header>
<soap:Body>
<Send xmlns="http://www.inwise.com/webservices/v2">
<source xsi:type="MobileMessageSendingSource">
<Message>
<AccountId xsi:nil="true" />
<Body>Test message body</Body>
<Bounces xsi:nil="true" />
<Charset>unicode</Charset>
<CreateDate xsi:nil="true" />
<EndDate xsi:nil="true" />
<LastSent xsi:nil="true" />
<RecipientType xsi:nil="true" />
<Sender>{YourNumber}</Sender>
<Sent xsi:nil="true" />
<Status xsi:nil="true" />
<TableConnectionId xsi:nil="true" />
<Unsubscribes xsi:nil="true" />
<UpdateDate xsi:nil="true" />
<Validity>1440</Validity>
</Message>
</source>
<target xsi:type="NewRecipientSendingTarget">
<Recipient>
<Id>0</Id>
<MobileNumber>{TargetNumber}</MobileNumber>
</Recipient>
</target>
</Send>
</soap:Body>
</soap:Envelope>