It is possible to form a SOAP request "manually", I did this on a server where SOAP::* was not installable.
You should do a (successful) SOAP-Request and trace the request and reply using tcpdump or any other tool. Otherwise you would need to rebuild the whole SOAP headers, etc.

This solution is not good at all. It will work as long as nothing at the API changes. Be prepared for unexpected updates which will require you to repeat the work.