Using xp_write_file in Sybase 12.5.4

I am using Sybase 12.5.4 on Windows 2003 Server. Are xp_write_file and xp_read_file Extended stored procedures available on 12.5.4.

I tried to use these in stored procedure, it gave me following error,

'Function xp_write_file not found,....'

I tried running query
sp_help xp_write_file in subsystemprocs. It shows 'Object does not exist in this database'.

In Syabse Central, Extended Stored Procedures section doesn't list these things.

Is it possible to get these in 12.5.4 or Extended Stored Procedure needs to be written?

Can anybody help me? Thanks!