NSTimer in SleepMode

[arsalananwar]

i'm working on application , in which i've use NSTimer, everything works fine, i've followed playing empty sound method to prevent iphone from deep sleep, also timer working fine in sleepmode , but if i turn iphone to silent mode, the timer stops working after 20 seconds (in sleep mode).

i've tried every single method i've found after Googling.

any help would be appreciated.

Thanks.

Arsalan