Vista - Set PropertyGrid Value

I set a property grid to show the properties for a command button.

mypropgrid.selectedobject = myButton

How can I, from another button on the winform, update a property on the
property sheet so it shows the new property? Seems like it should be the
simplest thing. Code example would be appreciated. Going in circles with
this.

To add some more information, I know how to do this if I am using my own
class in the property grid. For example:

Dim prop As PropertiesStandaloneLabel = New PropertiesStandaloneLabel()
propGrid.SelectedObject = prop
prop.MyProperty = SomeValue

But when I simply set the property grid to a control, and see all the dotnet
properties, I cannot figure out how to do the same thing. Any ideas on how
to do the equivalent code above?