Yeah, he could be implying cascading parameters. It is just not clear (beyond a reasonable doubt) from the post itself.

In SSRS 2005 I notice stored procedures in the dataset do not produce the ALL option as an "array" item to a paramater when that parameter is a multi-value one and has its available values tied to a dataset. Hard coding the dataset in the report does. For instance,

SELECT customerName form Customer

will show the individual customers and the ALL option in the drop down for the corresponding multi-value report parameter.