sendsms and smsc parameter

As someone pointed out sometime ago,
if you have multiple smsc, the parameter smsc in sendsms url does not work.
I know the routing  can be done by properly write the kannel conf file,
but I would like to choose it from a web page time by time, so the only thing is
to have the parameter working.
As in the conf file the name is smsc-id not smsc, I hope the doc tell the truth saying
the parameter name in sendsms is smsc.
It's difficult to solve it?
Thanks
Andrea