StandardFirmata on Due

At least I got another question concerning this topic.
In my current project I need to connect pure data pduino 0.5 with the Due board. When I was trying to upload the firmata 2.3.6 with Arduno 1.5.2 I got the following error:

StandardFirmata.ino:34: fatal error: Firmata.h: No such file or directory
compilation terminated.

but at least Firmata.h is in the same file as StandardFirmata.ino

Can someone give me a hint where to put the file fpr StandarFirmata.ino to find it?

System:
Mac OSX 10.6.8

Thanks for reply
yours
sebastian