How to get varchar by Entity framework (no replies)

Guys:

I use the vs 2011 +Entity framework + MySql Connecter. I hope to generate DB from Entity framework. But I got a problem to create varchar(xxx). In EDMX diagram design view, I set the data to "Fixed size=false, Max length=6000, type=string), after I click generating db, it always set the data type to longtext. but it works well if I generate MSSql script.

Does anyone knoe how to resolve it?

Thanks
Ming