Most of todays high-level synthesis tools offer a fixed set of interfaces to communicate with the outer world. A direct integration of custom IP in the datapath would often be more beneficial than an integration using such communication interfaces. If a certain interface protocol is not offered by the tool, either translation blocks (wrappers) are needed or the code should be written at a lower level. The former solution may hurt the performance, while the latter one is often impossible using an untimed high-level description. In this paper interface protocols or sets of IP core accesses are first described at a low level as sets of operations with scheduling information (macros). During the synthesis process, corresponding function calls are mapped to these macros. This facilitates the integration of custom-made hardware and hardware generated by high-level synthesis tools.