SAPNW::Rfc trapping VERSION

I'm trying to send the VERSION flag to BAPI_XMI_LOGON as follows:

SAPNW::Rfc->load_config;
my $rfc = SAPNW::Rfc->rfc_connect;
my $it = $rfc->function_lookup("BAPI_XMI_LOGON");
my $rc = $it->create_function_call;
$rc->EXTCOMPANY('TWDC');
$rc->EXTPRODUCT('MOPS');
$rc->INTERFACE('XMB');
$rc->VERSION('0.1');
$rc->invoke;

This works perfectly if I input the same information in SE37, but in my perl script, I get the error:

SAPNW::RFC::FunctionCall version 0.1 required--this is only version 0.02 at ./read-syslog.pl line 19

So instead of me being able to send a version number to the BAPI, the FunctionCall function is intercepting this version and interpreting it as a requirement for itself. Is there any way to avoid this behavior, and instead be able to pass the version number to the BAPI?

Cheers,

David.