Sample SOAP Envelopes from Documentation:
Perform SOAP Envelope
<s:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing">
<wsse:Security soapenv:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<wsse:UsernameToken wsu:Id="UsernameToken-30851894" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <wsse:Username>Username</wsse:Username>
<wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">Password</wsse:Password>
</wsse:UsernameToken>
</wsse:Security>
<wsa:To>https://webservice.exacttarget.com/Service.asmx</wsa:To>
<wsa:MessageID>urn:uuid:FAB69169EC56A8F9D51228490514867</wsa:MessageID>
<wsa:Action>Retrieve</wsa:Action>
</soapenv:Header>
<s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<PerformRequestMsg xmlns="http://exacttarget.com/wsdl/partnerAPI">
<Options></Options>
<Action>start</Action>
<Definitions>
<Definition xmlns:q1="http://exacttarget.com/wsdl/partnerAPI" xsi:type="q1:EmailSendDefinition">
<q1:ObjectID xsi:nil="true"></q1:ObjectID>
<q1:CustomerKey>7dc973cc-e0ab-4aec-9ba8-cf0b739e02dc</q1:CustomerKey>
<q1:Name>ESD_Name_7dc973cc-e0ab-4aec-9ba8-cf0b739e02dc</q1:Name>
<q1:Description>ESD_Desc_7dc973cc-e0ab-4aec-9ba8-cf0b739e02dc</q1:Description>
<q1:SendClassification>
<q1:ObjectID>51422ad6-6f65-de11-bf42-001e0bbb7678</q1:ObjectID>
</q1:SendClassification>
<q1:SendDefinitionList>
<q1:ObjectID xsi:nil="true"></q1:ObjectID>
<q1:CustomerKey>SDL CustomerKey</q1:CustomerKey>
<q1:SendDefinitionListType>SourceList</q1:SendDefinitionListType>
<q1:CustomObjectID>729860f8-7d66-de11-bf42-001e0bbb7678</q1:CustomObjectID>
<q1:DataSourceTypeID>CustomObject</q1:DataSourceTypeID>
<q1:Name>SDL Name</q1:Name>
</q1:SendDefinitionList>
<q1:Email>
<q1:ID>123</q1:ID>
<q1:ObjectID xsi:nil="true"></q1:ObjectID>
</q1:Email>
<q1:EmailSubject>ESD Email Subject</q1:EmailSubject>
<q1:Additional>cb99f3b1-67a4-452a-94c0-886e9a930961</q1:Additional>
</Definition>
</Definitions>
</PerformRequestMsg>
</s:Body>
</s:Envelope>
SOAP Request for Starting Email Send Definition
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Header>
<wsse:Security soapenv:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<wsse:UsernameToken wsu:Id="UsernameToken-28677619" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
<wsse:Username>username</wsse:Username>
<wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">password</wsse:Password>
</wsse:UsernameToken>
</wsse:Security>
</soapenv:Header>
<soapenv:Body>
<PerformRequestMsg xmlns="http://exacttarget.com/wsdl/partnerAPI">
<Options/>
<Action>start</Action>
<Definitions>
<Definition xsi:type="ns1:EmailSendDefinition" xmlns:ns1="http://exacttarget.com/wsdl/partnerAPI">
<CustomerKey>Market2Lead_Email_Definition_Key</CustomerKey>
</Definition>
</Definitions>
</PerformRequestMsg>
</soapenv:Body>
</soapenv:Envelope>