Creating a customised version of a preset button and applying it to one page works ok, but applying the same to a second page and form, seems to lose the mouseover effect.
Ahh... I see why, the ext has appended a value to the button name and created CSS code for it in the CSS file.
Why would it do that if I just wanted to add the same button to a different page?
I think the issue might be in whether you're actually saving your change (in this case, the addition of a cursor hover state) within your preset.
If you make a change to an existing preset (selecting an existing preset, choosing to edit that preset, and then making a change) without saving, it will do a 1 time insert of that button. The only way future inserts of the same button preset will include that change, is if you actually overwrite that preset name, or save as a new preset name.
For example, you start with 'Bloom'. You edit the preset, and add a cursor hover state. When you click 'OK' after making your edit, the Save Preset UI will appear. If you do not check the 'Save as preset' checkbox, the preset will not be overwritten and the insert of a button with your modifications to the preset will be a one time deal.
Are you checking 'Save as preset' and overwriting the preset name or saving as a new preset? If you are, and your modifications are not being carried in future inserts, there may be bug somewhere.
Hope this helps.