Just to add that I x-posted this to http://www.vguitarforums.com/ the modestly self-styled "largest Roland V-guitar resource on Earth!" and folk there seem to be having success too. Nice work, amitte.

Got it working!
 
Turns out I had my UA-25 set to Advanced Mode - 96 Khz sample rate, which means that you can only record, or playback (but not both). I had my set to 'record'. Switching to 48 Khz fixed the issue.
 
Amitte, you are a genius.

Thank You Thank You Thank You!!! You are a Genius! Method #2 Worked a treat!

EXCELLENT HACK! Thanks much!!

I have the Cakewalk UA-25EX USB Audio Capture....  I tried Amitte's method... seems to work in build 10240.  Very pleased.  Funny how you go accustomed to some things...  I wanted to keep using the UA-25EX USB Audio Capture because it has two audio outs.

Roland's product support is desperately weak in regard to this. The UA-25 EX has official status "driver in testing" for Windows 10 (as does my GR-55). These are both current products. AFAIK, there is no technology shift from 8.1 to 10 that would prevent any driver from working, as long as it can be installed. As we are experiencing, a simple alteration to the installer allows these Roland drivers to work as well as before. Why can't Roland at least alter the installers, even releasing them as betas if they have lingering concerns about compatibility? This is a rhetorical question, of course, now that Roland doesn't live here anymore. Microsoft must be very frustrated by this kind of behaviour from vendors like Roland - it's turning MS's product launch into the usual months of dragging annoyance, which is not want they wanted, I'm sure.
 

Thanks for this I have a friend who is running a V20 and I will try this on his Laptop.

Thanks a lot. Great work. It works on the V-Studio 20. I only had to use an other way to disable the driver signature. See this page:

 

Official UA25-EX driver for Windows 10 is now available here :   
EDIT : Sorry, as i am a new user, i cannot post URL ... So, check Roland official website, you'll find all infos on UA25-EX drivers page. All Roland products compatibility page have been updated as well. 

I have to put a HUGE thank you out  as my entire center is the vs700 set,
as for the editrol ua25ex roland did supply a update Now. just go to device manager
look for your edirol,right click update driver. (search internet) as long as your previous
os diver was already there .If not go to roland and download your last systems driver.
have your ua25ex plugged in.
Thanks again, to Helmet Schmitt
we are lucky to have his tech smarts and proves there are still some good people in
the world.