Check a checkbox in PDF form

[skacutter]

Why is this so difficult? I can fill in all the text values in my pdf form but I cant seem to activate a checkbox. How can you Enable, Activate, Check a checkbox using JSO? Here is how I fill a text filed

jso.getField("topmostSubform[0].Page1[0].textbox1[0]").Value = "Something"

When the object is a checkbox I have tried
.Value = 1
.Value = yes
.Value = checked
.Value = ok
.Value = true

Nothing seems to work... Please help