It's in my post
"Env. attack time modify (vv=40H no modify)" - I thought that's what you were asking for.

The message should start/end with F0/F7 respectively.

The numbers are all that matter. NRPN just means Non-Registered Parameter Number
All the Hex Code (the middle row of numbers) should be in between a F0/F7

If you've not done this before there's good/bad news.
Good: sending a 'wrong' SYSEX message will not do anything harmful so pretty safe to experiment, and it's very cool and powerful when it does.
Bad: Without good examples for your specific device it will be difficult to have success, since every device has different requirements for the data.

I don't own your device so can't experiment but I would think with a little luck what they did supply in the manual will at least be a good clue.
According to the PDF it appears in the manual as below image shows
I assume the center row of Hex code between the opening and closing F0/F7 data.
'vv' is the attack value, and you'll have to get an understanding of Hex values to understand how to speed up the attack or slow it down (the vv part of the image/code)
SYSEX requires some working knowledge of Hex IMO.

Attached Files (Click to download or enlarge) (Only available when you are logged in)
sysexKetron.jpg (87.96 KB, 30 downloads)
Last edited by rharv; 07/03/19 01:22 PM.
Make your sound your own!
.. I do not work here, but the benefits are still awesome