Lunch android secret code via B4A App : How can i lunch *#*#xxxx#*#* code with B4A.

Here is my code..

    Dim st,stt As String
    Dim su As StringUtils
    Dim ph As Intent

    st = "#"
    stt = su.EncodeUrl(st,"UTF8")
    Dim ussd As String = "*"&stt&"3646633"&stt&"*"stt&"*"
    ph.Initialize(ph.ACTION_CALL,"tel:"&ussd)
    StartActivity(ph)

After lunch app, it showed dialer only. I want to lunch engineering mode directly.