If you're good at turning on the charm, well done! It's taken me years to figure out how to do that, and I still do it only to a very basic level.
To the guys who are being nasty about this, the charm is an essential part of human nature, as it uses sexual lure to attract males (potential suitors) so a potential relationship can be formed. Guys also have an equivalent to "the charm" (that doesn't seem to have a particular name) where they tend to show off their muscles, talk in a certain way, pose, that sort of thing. It's human nature, and not some "evil" manipulation.
I think what you mean here is that you're having trouble figuring out how to actually technically get into a relationship. This is NOT easy, for anyone - girls or guys, especially with aspergers. It took me years to figure out a way to do this, how to get from A to B, but other people didn't understand why it was such an issue/so hard for me.
At first I thought, ok, so you try to be yourself and be attractive around a guy you like, and eventually that guy will ask you out. Wrong. I found this didn't work, as no guy ever asked me out. Clearly I was doing something wrong, or sending out the wrong signals, or maybe it didn't work that way.
The truth is, I have NEVER figured out how a normal girl gets a guy (whom she likes/she feels she has a two way connection to) to ask her out and begin a relationship. It has never happened that way to me. But once I realized this wasn't going to work/happen, and there was no way I would ever get the signals right/figure out how to actually seduce someone, I decided I needed to figure out another way to get from A to B.
In the end, with the guys I was close friends with and attracted to, and wanted to take things to the next level with, I ended up simply fronting up to them and asking them; will you be my bf? They will either say yes or no, but if they say yes then you're through. I think the normal way to go about things is to go on dates with people and somehow slowly merge friendship into a relationship, but that process is way more complicated and full of subtle signals and cues an aspie could never hope to pick up on, so I think we need to work out alternate pathways.
It's not really a typical approach, but it has worked for me 50% of the time. It's worth a shot.
Learning how to kiss someone I liked (when I had never kissed someone before) was the same for me, even though people wouldn't get what's so hard about it. It took me months and detailed comprehensive instruction from my brother to finally figure out how to do it. The thing is, you can't just really lean forward and bump your lips with someone. The social cues have to all be right first.
_________________
Into the dark...