Windows 7 uses variants of PTP operations, that previously testes OS's didn't use, therefore implementations of those operations were untested and unsurprisingly contained bugs. As of commit ef7ef29b5cdcf8630c901362a66905b956242e0d these bugs are fixed and ptp-gadget is now also compatible with Windows 7 and works in both "camera" and "Windows explorer" modes.
After a long fight trying to find a combination of parameters, that would satisfy the Microsoft PTP driver, using logs recorded from real Canon digital cameras, it turned out, that the line "T is a constant character" in the DateTime string definition in the PIMA 15740:2000 standard should actually be interpreted "the literal 'T' character." Adhering to this at last made Windows happy. This achievement has been proudly marked with tag v1.0. On the way to this milestone ptp-gadget has also acquired a DCF filesystem, all images are now reported under /store_00010001/DCIM/100LINUX/, this, however, is not a complete hierarchical filesystem implementation. Subdirectories are still not supported, the presented directory structure is absolutely static.
The project has been announced on the linux-usb mailing list in this post. As described in the headline article to this category, currently only downloading of images and thumbnails is supported. It has been positively tested with Linux hosts, running various distributions and gphoto2 versions, as well as with a Mac OS X tiger host. However, tests with Windows systems are still unsuccessful.