AWS Route53 - delegate subdomain

I created two public hosted zones in AWS Route53:

• domain.com
• sub.domain.com

In "sub.domain.com" zone I added "A" record for "test.sub.domain.com" name resolved to 10.0.1.5. I can resolve "test.sub.domain.com" name using "sub.domain.com" name servers.

> nslookup test.sub.domain.com <sub.domain.com server>

Name:    test.sub.domain.com
Address:  10.0.1.5

Following instruction for Creating a Subdomain That Uses Amazon Route 53 as the DNS Service, in "domain.com" zone I added "NS" record for "sub.domain.com" pointed to the "sub.domain.com" zone name servers. Now, when I try to resolve "test.sub.domain.com" name using "domain.com" zone name servers, I get response that name is served by "sub.domain.com" servers, but it cannot resolve to IP address. Below is example of "nslookup" response:

> nslookup test.sub.domain.com <domain.com server>
Name:    test.sub.domain.com
Served by:
- <sub.domain.com server>

          sub.domain.com

Does Route53 support subdomain delegation to other Route53 servers? Have I missed something in the configuration?