If you have a job that runs multiple dts packages, the process you have documented would be long and laborious....

I generally use the DTSRUNUI.exe executable...

1) >start>Run>DTSRUNUI 

2) Specify SQL Server you want to get encrypted command for and the login credentials you want the job to use to run.

3) click the "..." next to package name

4) Click the "advanced" button

5) Specify variables if you want to...

6) Click the bullet for "Encrypt the command"

7) Click the "Generate" button

8) copy n' paste the line of text that is generated into the step of your dts package...

Wahlah, nice and easy... DTSRUNUI is seperate from enterprise manager, so you can have both apps up at the same time...