This is a general, as I wish to configure a dialy evening backup job for all our devices.

This is one of the main features of CiscoWorks Resource Manager Essentials which is part of the LAN Management Solution bundle (http://www.cisco.com/en/US/products/sw/cscowork/ps2425/index.html). There are also Open Source tools such as Rancid which can help you do this (http://www.shrubbery.net/rancid/). You could also script this yourself using a language like Expect (http://expect.nist.gov/) or using SNMP and the CISCO-CONFIG-COPY-MIB (http://www.cisco.com/en/US/tech/tk648/tk362/technologies_configuration_example09186a0080094aa6.shtml).

Finally, newer versions of IOS support a built-in config archive capability which can periodically backup your configuration to local flash or to a network server. See http://www.cisco.com/en/US/docs/ios/12_3t/12_3t7/feature/guide/gtrollbk.html#wp1100253 for more details.