in qtractor you can have access to custom presets from the plugin properties dialog aka. generic stock plugin UI. there you have all the necessary controls in the upper left side of the generic plugin window.
however there are some differences whether it applies to a LV2 or a VST plugin, being the most notable the following:
LV2 plugins: the named preset is a genuine LV2 state preset which is implicitly stored on the file-system (default is ~/.lv2) under the proper LV2 spec. therefore you may see that some plugins already provide there their so called "factory presets" that comes with installation;
VST presets (and any other but LV2): the preset names you may define here are private to qtractor, depending on each plugin implementation, these presets can be mapped and stored to qtractor's configuration and/or the general file-system, on a preset file and name at your discretion. this preset file is specific to qtractor and usually goes with the .qtx suffix on its file-name.
note that the initial preset drop-down list is of course empty because of that custom, private qtractor designation, so you won't find any "factory presets" here--you have to set up your own;
and finally, at the time of this writing, current git head (master branch; qtractor v0.7.1.8+), already has support for loading and saving, to and from .fxp/.fxb files--of course that applies to VST plugins only.
in qtractor you can have access to custom presets from the plugin properties dialog aka. generic stock plugin UI. there you have all the necessary controls in the upper left side of the generic plugin window.
however there are some differences whether it applies to a LV2 or a VST plugin, being the most notable the following:
note that the initial preset drop-down list is of course empty because of that custom, private qtractor designation, so you won't find any "factory presets" here--you have to set up your own;
and finally, at the time of this writing, current git head (master branch; qtractor v0.7.1.8+), already has support for loading and saving, to and from .fxp/.fxb files--of course that applies to VST plugins only.
hth.
cheers