I introduce you a chinese website that able to sign .sis file online. Here the website address

http://s60.vgooo.com:801/

for those users can’t read chinese word , here is the guides and step by step how to signed online ……

STEP 1

Press register button to register if you don’t have account.

STEP 2

Enter your desired username , password , confirm password and e-mail ,and then press register button, it pretty fast to register and no confirmation e-mail needed.

STEP 3

Enter your handphone 15 digit IMEI number and then press submit button , example 353641012080185 . IMEI number can be founded by key in *#06# in your nokia handphone.

STEP 4

After press submit button , the site will mention about your application are under process , usually it takes 1 day to approve your IMEI number .

STEP 5

Wait for 1 or 2 day , go back http://s60.vgooo.com:801/ login and check . Suprise ! it will pop up a small window say that your IMEI was approved .

STEP 6

Browse and select your .sis file , and then press upload ! Wait for file finish upload .

STEP 7

DONE !! Click the link to download the signed .sis file ! And install to your nokia handphone .

I tested myself and it really work.
signed online website : http://s60.vgooo.com:801/
file tested : Warelex.Mobiola.WebCam.USB.v1.04.S60v3.SymbianOS9.1.Unsigned.Cracked-BiNPDA.sis
handphone : nokia n73