It is not possible to use external jar files with in CMD for sending SMS messages. However, please let us know the functionality of the jar file, so that we can verify if we can achieve your requirement by using CMD "External Processes" functionality.
It is not possible to call external webservice/jar files with in CMD for connecting/sending SMS as CMD binaries can read only OOTB jar files. Is there any specific reason for using external webservice for sending SMS?
Our Engineering Team wants us to invoke their SDP (Service Delivery Platform) web service to send out SMS. That's why I am exploring if Chordiant Marketing Director can invoke directly with the SDP web service to send out SMS. Otherwise, I will have to dump out the contacts to a flat file, maintain/call another batch job to interact with the SDP web service. There will be much more coordination, development and maintenance work if we go by the latter way.
If the web service configuration is same as SMSC configuration (if web service has same parameters to configure in CMD screen as a SMSC server), then CMD services will connect to web service. Else, you can direct the output to a file/table and use web service to deliver SMS.