I believe you're referring to a method in 'Web Services for Microsoft Dynamics'.
I don't use that, personally, it's too big and hairy for me. But, if you read the help file, they do tell you how to loop through and grab 1000 at a time until you're done.
Me, I'd sooner code
SELECT * FROM IV00101
and be done with it. <smiles>
I write stored prodedures to get what I want OUT. Just don't send data IN to Dynamics without using eConnect. Unless you're REALLY sure what you're doing.