This is easy to do. If I understand you correctly you want to make a new style preset......meaning you want to change the sounds you play on the right hand while playing the style. The style presets allow for 10 different combinations. The factory usually gives you six to start and you can add 4 more or you can erase theirs and use yours. Here's what to do. From the main screen select the section called keyboard parts....not style parts. Here you can change from two uppers and two lowers or just use one upper. You must first use the function buttons on the left to select the upper one or upper two section and then after you select it hit the same function button again to either mute or turn the track on. You know you've turned it on when you see an icon of a keyboard rather than a mute icon. Once you've selected the part you then go and choose any preset sound or individual voice sound (or if you are layering two you select two different sounds) and when you are happy with these sounds and you've used the volume sliders to adjust the level of one or both you then hit the write button all the way over on the right side of the keyboard. Now you have some choices. You will see I beleive (I'm at home right now and doing all of this from memory) Preset, Performance and style preset. Choose style preset by using the cursor to move over to this. You will now see three boxes under the choice for naming, what's in the current location and now you can choose an empty location or overwrite onto one you don't care about. When you do this and then hit enter, your sounds will be memorized as a style preset. Now, whenever you call up this style, when you hit style preset you will see your new selection along with the ones already there. I beleive, but am not sure, that whatever is in location 1(top left) will be the one called up when you recall a style but I'm not positive if you can change this or not.
I hope this helps,
Kaye's Music Scene