How I can extend existed editors in baseLanguage

Now you have to copy-paste existing editor from super-concept and then modify it.

It's possible to create reusable editor components (#_DeprecatedPart#, #HasAnnotation_AnnotationComponent#, .. in InstanceMethodDeclaration editor), but it's not possible to somehow extend already defined editor for a concept now.

You probably don't want to change only the editor but also the structure to add attributes.
The easiest way IMHO is to create an own concept that extends the existing concept.

There is also a way of using annotation links.
Hopefully some other guys can you tell you about that.

Did you already watch the tutorial by markus voelter: http://www.jetbrains.com/mps/documentation/index.html "Building The Language"

It is also interesting how to use annotation links in MPS 2.0. Can anyone give me a guide?

In MPS 2.0 "annotation links" become "attributes".
Attribute is a special concept instance of which can be a child of any concept. There are 3 type of attributes: NodeAttribute, LinkAttribute and PropertyAttribute. Link and Property attributes has a relation (connection) to the reference or property of the attributed node.
For these we have a special constructs in smodel language. You can derive you own attribute from NodeAttribute, LinkAttribute or PropertyAttribute concepts, give a name to the attribute (role) and specify if this 1-1 or 1-many attribute. Also you can specify applicable concept for the attribute and of course the attribute itself structure. After that you can refer to the defined attribute with the
node.@attributeRole1
node.@attributeRole2<link>
node.@attributeRole3<property>
If the node is applicable concept for the defined attribute. You can use these expressions as usual features (links or properies) in smodel langauge, e.g.:
  node.@attr = new node<Classifier>;   node.@attr.method;   node.@linkattr<linkname>.add(xxx);
Thus you can add functionality to the existent concepts without modifying them.
In MPS generator's templates are implemented using macro attributes.

Do you have more questions on attributes?

Good point! Thank you!