Extending a schema

I am currently creating an overview over installed software in an organization. To do this I am distributing and collecting questionaires (represented as excel forms) from all employees.
This is a tedious process, and I am trying to find a better way to handle the whole process. I am thinking one solution could be to register the information on installed software for each employee as part of the allready existing Active Directory structure. This could be done by extending existing schemas to cover information on "needed software" (list) and "currently installed software" (list). I am not sure it is a good idea to use AD for this purpose, but regardless I need some kind of mapping between employees and needed software and currently installed software.
Any viewpoints on whether this is a good solution or not? I am also interested in hints on other solutions. I have looked at the Iana ldap schemas but I have so far found no match for my/our needs.