Upon Breck Carter request I am posting a new question. I can not reproduce this issue in SA 12.0.1.3994 or later, in other words after SQL Anywhere switched to OpenSSL everything works fine, but SQL Anywhere 11.0.0.3113 is the version I need to be able to communicate with SOAP web service.

This is the function I use to get data from a webservice:

CREATE FUNCTION WebServiceCall(in wsurl varchar(2048), in wsns varchar(2048), in cert varchar(2048),
    in username varchar(128), in password varchar(128), in idnum varchar(128), in productNumber varchar(128), in lang varchar(128))
RETURNS xml
url '!wsurl' type 'SOAP:DOC' namespace '!wsns' certificate 'cert=!cert' set 'SOAP(op=GetSaisWithPdf)';

Calling it I get this error:

There was an error reading the results of the SQL statement. The displayed results may be incorrect or incomplete. HTTP request failed. Status code '0' SQLCODE=-983, ODBC 3 State="HY000"

And this is what I get in the log file (sensitive data is hidden, sorry for that):

[connid = 18, 04/02 13:41:05.315]
[connid = 18, 04/02 13:41:05.315, REQUEST]
POST /***/SAIS/WebServices/getsais.asmx HTTP/1.0
Content-Type: text/xml; charset=windows-1257
Connection: close
ASA-Id: 26edeefbd1c2403f9210fb4554217ad4
Content-Length: 528
Accept-Charset: windows-1257, UTF-8, *
Date: Wed, 02 Apr 2014 10:41:05 GMT
Host: ***
SOAPAction: "http://tempuri.org/GetSaisWithPdf"
User-Agent: SQLAnywhere/11.0.1.3113

<?xml version="1.0"?>
<SOAP-ENV:Envelope
  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:m="http://tempuri.org/">
  <SOAP-ENV:Body>
    <m:GetSaisWithPdf>
      <m:username>***</m:username>
      <m:password>***</m:password>
      <m:idnum>***</m:idnum>
      <m:productNumber>***</m:productNumber>
      <m:lang>***</m:lang>
    </m:GetSaisWithPdf>
  </SOAP-ENV:Body>
</SOAP-ENV:Envelope>
[connid = 18, 04/02 13:41:33.568, RESPONSE]
H
[connid = 18, 04/02 13:41:33.573, RESPONSE]
TTP/1.1 200 OK
Cache-Control: private, max-age=0
Content-Type: text/xml; charset=utf-8
Server: Microsoft-IIS/8.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
S: 1
Date: Wed, 02 Apr 2014 10:41:32 GMT
Connection: close
Content-Length: 1207257

<?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:Body><GetSaisWithPdfResponse xmlns="http://tempuri.org/"><GetSaisWithPdfResult><XmlDocument><root xmlns=""> <InfoBlock name="tblInfoBlock" title="Santrauka" sectionId="santrauka"> </InfoBlock><Summary name="tblSummary" UnknownValue="Nenustatyta"> <vat Name="Vėlavimo atsiskaityti reitingas" Probability="83,00%" ProbabilityText="tikimybė," ClassValue="10" ClassText="klasė," ClassName="Aukščiausia rizika" IsSet="true" /><bt Name="Bankroto reitingas" Probability="5,033%" ProbabilityText="tikimybė," ClassValue="8" ClassText="klasė," ClassName="A
[connid = 18, Protocol Error]
[connid = 18, socket closed]
[connid = 18, Error: socket closed by peer]

As you can see, the response is truncated to 1024 characters, I contacted the web service maintainers and they confirmed that they send out the full response, I tried the same request (envelope generated by SA) in SoapUI and in C# and got correct results, no truncation. Also, as mentioned before, it works perfectly with latest SA12 EBF. So any ideas whats wrong? I tried reading the 12.0.1.3994 EBF release notes but could not find anything related to my problem.