So I listened to the song. First time I have ever heard it as I can’t say I’m too familiar with this era of the scorpions. I’m guessing this is the lick the op wants to sub for. This is just my transcription based on what I hear and most likely’s, but I’m guessing Michael Schenker is playing something pretty close to this:
EDIT
(I re-listened and I’m pretty sure he is ho-po trilling the first three notes which makes the phrase easier)
Now if I were to use a strict USX to try to play it similar to how someone like YJM would, I might recommend fingering it like this, although it may not be the easiest to play for some if they aren’t used to economy picking.
(Note you can keep the trill just like the first, and get rid of the upstroke on the grill part and the picking convention is the same)
Although part me feels like taking maybe a Paul Gilbert approach and adding in strategic pull off’s may even be an easier way to play it. Listening to it I almost suspect Michael Schenker is playing more similarly to this, and it’s not all alternate picked. It was hard to tell on the recording though:
Now if the lick is a bit too much right now as is, cut out enough to make it easier but still keep the vibe of it especially if you were writing the lick as a sub when performing the song. I would maybe keep that ending though since it ties it together. I will take a look at the lick @kgk posted in the post above to see about fingering and such, but not sure about keeping it mostly on one string unless that it the easiest way you find to play it.
EDIT #2
So I looked at options to simplifying the lick so that it still captured the same-ish vibe of the original but makes it maybe not as difficult to play.
This first breaks the grouping down into 16th’s and keeps everything mostly in one position but also keeps an upward escape for some one who plays that way.
The second breaks it down further into eighth notes but still requires crossing strings.
And the third is a doctored version of the one @kgk posted if one feels compelled to keep it on one string.