The accounting of IT-costs is an important aspect not only in the context of corporate cost accounting in general, but also for the management of IT. Various approaches to IT-cost accounting exist. However, they usually are implemented with only loose integration to the company´s IT-management. This often causes discrepancies between the numbers used for accounting and those for planning and operating the IT. A tighter integration of the information basis, which the two corporate functions (cost accounting and IT-management) share, is suggested, to solve this problem. One way to achieve this integration, is the implementation of cost accounting concepts in an IT-management method. In this paper we introduce concepts for modelling IT-costs within a domain specific language for the modelling of IT-landscapes. The language is part of an IT-management method, which is currently under development. Using these concepts, costs can be modelled on the same level of abstraction as IT-components, thereby establishing a higher integration level between corporate cost accounting and IT-management.