Changing .Net default value for twodigityearmax

In VB, VS2005, I want

Dim s as String = "1/12/31"
Dim d As Date = CType(s, Date)

to return a date with a year of 2031, as opposed to 1931, which it does now.

I believe I want to change the system's twodigityearmax to 2049 rather than
2029, which appears to be the default.

How do I do that, so that CType uses the new twodigityearmax?

Thanks for your help!