No, you'll need to create another Live ID and attach it to US or SG.

yup, you can sign 2 or 3 id, USSD code wont work on WP7.

that code for symbian phone

sry .. mis inform bout the *100#, i tot your talking bout the *#0000#....

for digi prepaid i use *116# for setting the data. i got some problem when try to access that while using lumia 800.

try pull out the sim card and plug it to another phone~

or you can just stop Lumia for using the data by turn it off at "Data connection" under setting > mobile network...

np... the phone use some of my credit as well but digi will stop at rm8, and then the whole day will be free for using the data ~

for your case it is much painful ... huhu...

just turn it off the "data connection" under "setting" > "mobile connection", so the phone wont go online using the phone credit...

maxis 10min - RM105?? or RM1.05??

i believe no one will go complain if its just rm1.05 

Time to get unlimited plan, peace of mind.

you should keep the frame of the sim card...

Sorry... Just wondering..
You can't reply the *100# code or you can't send the code at all...
If you can't reply... You can combine the whole code at one go..

For example (i don't use hotlink prepaid right now... So this is just a rough sample..)
*100# --> Hotlink menu
2 --> Balance

Instead.. You can just type *100*2#
Just use *100*x*x*x# code..