ICT_SERVICE_DESK_API requestor and provider GUIDS

Hi all!! im using service definition ICT_SERVICE_DESK_API

I need to create from 3rd party service desk, an incident in Solman.

So Requestor here is 3rd party system e.g. SOAPui ver. 4.5.1

and Provider is Solman.

There is Function RequestSystemGuid it returns GUID of the system. If i launch this request from SOAPui(requestor) it returns systemguid XXX and this guid = SOLMAN guid( checked in my solman table ICT_SYSGUID.

But How i can get SOAPui's GUID??? In my example SOAPui are not connected to solman directly, so in SOLMAN there is no information about SOAPui and i don't need it!

So now i can't get ( SOAPui ) Requestor's GUID...

Is it mandatory to connect system to solman and then take GUID from table ICT_SYSGUID or where else i can get it ??? help plz.

Regards Dan