Sip Platform using voipswitch

We are looking at installing 'voipswitch' a windows based voip software softswitch to run a SIP VoIP platform. The software offers basic media features, voicemail & call forwarding. We would like to add some more features that are based around customer call features such as last call trace (UK 1471 service) and Caller Blacklist and Anonymous call block, all available by dialling service numbers.. All the information pertaing to such services would be held in CDR's i.e. telephone numbers. If it is possible to impliment these services and anymore we would like to hear from you. The switch runs on Windows XP/Server 2003 and MySQL DB. I can supply a Demo of the software for anyone who would like to have a look at it... Also, the software has the ability to offer FREE call minutes but at present this can only be done by giving 'Grace periods' per call , what we need is for it to be able to calculate a 'lot' of accrued minutes per account, in bundles such as 500 FREE or 1000 Free call minutes, but only to one country code. I heard this can be done but not sure how. This in turn would enable us to offer different call plans with Bundles of Free call minutes. Sorry to sound vague but I am not a programmer....