Modules & VBA :: Use Default Value To Store Data

I'm trying to use a form to store some usefull data on my database.

I'm using the DefaultValue property of the TextBoxes in this code:

Code:
Sub Comando17_Click()
Testo4.DefaultValue = """sasso"""
Testo6.DefaultValue = """sdr"""
Testo0.DefaultValue = Testo0.Value
DoCmd.Save
End Sub

Comando17 is the name of the button to run the macro
Testo4, Testo6 and Testo0 are the names of my TextBoxes
sasso and sdr are the values I want to set as Default

When I run this macro it changes the DefaultValue property on VBA local variables and the Value property, but the DefaultValue on the form structure remains unchanged.