It depends on what exactly you want to do. I assume that you want to programmatically insert a link into a request. There are different ways to do that.
1) Use a URL field in a request. This can be filled using ksc_store special command.
2) Use a standard text field and fill it with a HTML link (start content with ""). This can also be filled using ksc_store special command.
3) Use a link or even an attachment in the references section. There is no standard (documented) API to do this, but it's possible through the database. If you want to go this way please let me know and I can provide you with an example.
I appreciate your reply. We decided the best approach is to activate a JSP. The JSP has to be activated from within a task or event, and must have the ability to read some task or event parameters. The question would be how can I launch a jsp from the PPM screens, can we have a filed with default url, and where do we find the commands or api that could be used to read like task unique id, task date etc.. to pass that info to our created jsp. I learned that the current version of PPM is SOA compliant and has a well defined webservices. this is the route that we need to take. please advise.