There is no way to avoid hard coding the path to iw-home in DCT's. I believe there is a feature request asking to be able to use a token of some sorts for this, but it has never been implemented. You can try contacting support and having your company added to the FR.
What is the purpose behind this request? Do you just not like hard coding stuff (who does?), or do you have multiple environments with different iw-home locations? If it's the latter, you could probably create your DCTs with some token in them like %%IWHOME%%. Then whenever you deploy your DCT to a new branch/environment, you could have some wrapper script that would replace all of the %%IWHOME%% tokens with the path to iw-home for that environment.
Other than that, you're pretty much out of luck.
~Jeff
