I've never used SHELL in Navision, but if the code will run on the server, then you should be able to use SHELL to call DTSRun - a command line exe that runs DTS packages. If you will be running the code from a client other than the SQL Server, then you'll need to use ADO.
Comments
MaintenancePlan is a job.
Here is an example on how to use ADO.
http://www.mibuso.com/forum/viewtopic.php?t=2401&highlight=ado+connect
Independent Consultant/Developer
blog: https://dynamicsuser.net/nav/b/ara3n
cheers,
chris