Creation Of Dynamic Checkboxes

I have a UserForm with a CommandButton; when I click on it a function creating dynamic checkboxes on another UserForm is implemented and then this second UserForm is displayed (and the dynamic checkboxes are displayed too).

Code:
Private Sub cmd_BUTTON_Click()
If MsgBox("Are you sure you want to add Dynamic CheckBoxes?", vbQuestion + vbOKCancel, "") = vbOK Then
UserForm1.Hide
UserForm2.Caption = "DYNAMIC CHECKBOXES"
Create_DynamicCheckboxes
End If
End Sub

Code:
Sub Create_DynamicCheckboxes()
Dim CheckBoxTop As Integer
CheckBoxTop = 75
Dim i As Integer
For i = 1 To 10
Set theCheckBox_ID = UserForm2.Controls.Add("Forms.CheckBox.1")

[Code] .........

Everything work fine!!!

Now I have the UserForm2 displayed that include 10 CheckBoxes, which names should be:

chk_1chk_2chk_3chk_4chk_5chk_6chk_7chk_8chk_9chk_10

Why the following code doesn't work???

Code:
Private Sub chk_1_Click()
MsgBox(chk_1.Value)
End Sub