Getting your Manga published

You probably have an epic story on your mind that you cannot wait to get published.
But what's the best way to approach a publisher? Would you send in 100 pages readily inked and screen-toned?

On the internet site of the German publisher Carlsen Comics it tells you to submit a single project you would like to realize. Tell them what genre your story belongs to, how extensive the story is planned to be (epic, short story, etc...) and submit a short summary. They want character sheets of every main character in different poses and with different expressions on separate sheets. For side characters, settings and machinery they only need sketches. They only want 4-6 finished pages of your manga that represent it. So if you send in your first 3 volumes it's likely they won't even bother to look at what you drew.

Now I have also read a manga called "Bakuman" that I can only recommend to any mangaka in spe.
In this manga two aspiring mangaka make their way into the world's most famous manga magazine "Weekly Shonen Jump". It is explained that Jump expects mangaka in spe to submit the first 3 chapters of their manga for review. That's a lot closer to the 100 pages you were gonna submit and they can probably get a better insight of your manga.
But it's 3 chapters. No more, no less.
You may have the whole story in your head already but it's inadvisable to draw them all out.
Weekly Shonen Jump has a questionnaire that determines how popular each manga they publish is.
If your manga is not popular, your editor may tell you to change the direction of your manga in order to save it. That's why you're always only 3 chapters ahead of what's being published.

So my advice before applying to any publisher - call them and ask specifically what they want and expect.