The problem is that calling a long-lived process from a short lived is not an easy thing to do. At least right out of the box.
There are a couple of ways around it however.
1 - call your long lived process (from your short lived process) using the WebService.InvokeWebService operation. Essentially you are doing the same thing in LC that you are doing in your .Net application
2 - write a custom component (a DSC) that uses the LiveCycle APIs to call the long lived process. You would then include the DSC in your short lived process.