Problem with code night and day

Goodmorning excuse for my english.

i have a s50 and i have this problem:

i must set the night time condition with this plain: 

fx0 to extension 20

fx1 to extension 21

etc 

in this mode the s50 crete one code service for plain ad example:

*812

*813

etc

i must insert the night with one dds key of phone and not setting one key for each time condition. 

there is a way for this ? 

thnak you very much 

Marco Italy