use SOAP::Lite;

my $soap_client = SOAP::Lite->uri('myuri')
                    ->proxy('http://serviceendpoint',
                            timeout    => 30,
                            keep_alive => 1);
for (1 .. 10) {
    if(fork()) {
      #--- do something in parent
      #-- like wait for time specified by load rate etc.
      sleep(1); #--- just for pseudo code
    }
    else {
       $soap_client->call('SomeMethod',$paramter);
    }
}