.htaccess: regex works in text editor, not in .htaccess redirect

[emergence]

Hello everyone,

I'm trying to set up a redirect that sends people to the right language subdirectory:

If the come throught the example.com or example.eu Domain (example.com/cur/...) without any language subdirectory (/en or /de), I want to send them to example.com/cur/en/...

And if they come through the example.de domain, and they don't have any language subdirectory, I want to send them to example.de/cur/de/...

My .htaccess:

<IfModule mod_rewrite.c>
RewriteEngine On
#RewriteBase /cur/

RewriteRule ^http://(www\.)?example\.(eu|com)/cur((?!/en|/de).)*$ http://$1example.$2/cur/en$4 [R=301,L]
RewriteRule ^http://(www\.)?example\.(de)/cur((?!/en|/de).)*$ http://$1example.$2/cur/de$4 [R=301,L]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /cur/index.php [L]
</IfModule>

Can you see what I'm missing/messing up?

Thanks a lot!