Yes, you will need to modify or create another external task to use the deploy feature. The OOTB deploy task doesn't have that many options as using multi select servers to pass in as parameter substitution.
I do not remember a SP2 for 721. There was a single large patch and that must be applied to TS as well as LS
... I do not believe that LSCS in 7.2.1 SP1 properly recognizes custom target nodes.
when i check the deployment task(which is external task) i couldnot find the class that it is referring to as there is no class variable.
By default, the DeploymentTask uses this class. I don't believe the source code is published anywhere though, so you might need to roll your own if you need any changes.com.interwoven.ui.teamsite.workflow.task.urltask.DeployURLExternalTaskWhat would be easiest though, is to either use a configurable variable as the odDeploymentName value (or any of your odSubst_ variables, depending on how you've built it), or to create an external task that modifies that variable prior to arriving at your deployment task.