Метод возвращает идентификаторы - номера всех подписок, которые были изменены, у которых версия больше указанной. Если byAllLogins = true, метод вернет все подписки, созданные всеми логинами юр. лица, относящегося к Вашему логину. Если byAllLogins = true, метод вернет только те подписки, которые были созданы только из-под вашего логина.

GET https://sandbox.mont.ru/Version2/Service/B2BServiceV2Xml.svc/GetSubscriptionsId?version=0&byAllLogins=true

<?xml version="1.0" encoding="utf-8"?>
<GetSubscriptionsIdResponse xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <GetSubscriptionsIdResult>
    <Data>
      <Ids>
        <string>0979e3c0-638c-4ef1-a262-018a5414eda2</string>
        ...
        <string>SUFFER12-999d-439d-8ce0-131f424ee14c</string>
      </Ids>
      <LastVersion>23749140</LastVersion>
    </Data>
    <IsError>false</IsError>
    <ErrorCode>0</ErrorCode>
    <Errors/>
  </GetSubscriptionsIdResult>
</GetSubscriptionsIdResponse>

POST https://sandbox.mont.ru/Version2/Service/B2BServiceV2.svc

<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:tem="http://tempuri.org/">
  <soap:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"
               xmlns:wsrm="http://docs.oasis-open.org/ws-rx/wsrm/200702">
    <wsse:Security soap:mustUnderstand="true"
                   xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
                   xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
      <wsse:UsernameToken wsu:Id="UsernameToken-0C97A913BFEA47D23B14440332992609">
        <wsse:Username>login</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:Nonce
          EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary">
          +9s1Gn8qnXZCIl4/GSBL2Q==
        </wsse:Nonce>
        <wsu:Created>2015-10-05T08:21:39.260Z</wsu:Created>
      </wsse:UsernameToken>
    </wsse:Security>
    <wsrm:Sequence>
      <wsrm:Identifier>
        s:Sender
        a:InvalidSecurity
      </wsrm:Identifier>
      <wsrm:MessageNumber>1</wsrm:MessageNumber>
    </wsrm:Sequence>
    <wsa:Action>http://tempuri.org/IB2BServiceV2/GetSubscriptionsId</wsa:Action>
    <wsa:MessageID>uuid:3542abf7-d202-414c-a7e7-e4c1c9f38f4e</wsa:MessageID>
    <wsa:To>https://tayga:453/Version2/Service/B2BServiceV2.svc</wsa:To>
  </soap:Header>
  <soap:Body>
    <tem:GetSubscriptionsId>
      <!--Optional:-->
      <tem:version>0</tem:version>
      <!--Optional:-->
      <tem:byAllLogins>true</tem:byAllLogins>
    </tem:GetSubscriptionsId>
  </soap:Body>
</soap:Envelope>

<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope" xmlns:a="http://www.w3.org/2005/08/addressing"
            xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
  <s:Header>
    <a:Action s:mustUnderstand="1">http://tempuri.org/IB2BServiceV2/GetSubscriptionsIdResponse</a:Action>
    <a:RelatesTo>uuid:3542abf7-d202-414c-a7e7-e4c1c9f38f4e</a:RelatesTo>
    <o:Security s:mustUnderstand="1"
                xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
      <u:Timestamp u:Id="_0">
        <u:Created>2015-10-05T08:21:38.566Z</u:Created><u:Expires>2015-10-05T08:26:38.566Z</u:Expires>
      </u:Timestamp>
    </o:Security>
  </s:Header>
  <s:Body>
    <GetSubscriptionsIdResponse xmlns="http://tempuri.org/">
      <GetSubscriptionsIdResult
        xmlns:b="http://schemas.datacontract.org/2004/07/WebStore2.B2B.Version2.Contracts.Responses"
        xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
        <b:Data>
          <Ids xmlns="">
            <Item>SUB-70</Item>
            ...
            <Item>SUB-71</Item>
          </Ids>
          <LastVersion xmlns="">8722632</LastVersion>
        </b:Data>
        <b:ErrorCode>0</b:ErrorCode><b:ErrorText /><b:Errors /><b:IsError>false</b:IsError>
      </GetSubscriptionsIdResult>
    </GetSubscriptionsIdResponse>
  </s:Body>
</s:Envelope>