How to create the default opportunity buttons in .NET API? (Next, Summary Report)

Hi,

I am trying to recreate 2 default buttons for the opportunity entity. These are the button called Next and Summary Report.

The problem with the first button is that it doesnt retrieve the next record and it also redirects to the default page.

The second button doesnt work at all.

Please see the source code of the buttons below:

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AddUrlButton("Next", "Next.gif", Url("260"));

AddUrlButton("Summary Report", "MenuBut_Reports.gif", Url("1440"));