There are no plans to add reflash tool functionality for STLINK-V3 and it is unlikely that there will be any in the foreseeable future.
The reflash utility was designed to provide J-Link support for ST evaluation boards, which did not come with headers for external debug probes.
ST promised, that all evaluation boards that come with a V3 would also come with an external debug header,
so J-Link can be supported out of the box.
As the ST-LINK reflash J-Link is not allowed to be used in a commercial context,
I would assume that you would want to use it non-commercially correct?
Keep in mind, this is *not* a support forum.
Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
Should you be entitled to support you can contact us via our support system: segger.com/ticket/ Or you can contact us via e-mail.