Confusion on jain-sip-1.2 and nist-sip-1.2 RI. Pls Help!

hi

I do have a confusion here. pls help!

I checked out jain-sip-1.2 source from 
is2.antd.nist.gov:/home/nist-sip/cvs-nist-sip-1.2/repository

and did ant builds for the following:
    - compileri -> Compiles the reference implementation.
    - compilestack -> Compiles the jainapi

then I have got JainSipApi1.2.jar & nist-sip-1.2.jar

I guess that nist-sip-1.2.jar is an implementation for JainSipApi1.2.jar

to my understanding nist-sip-1.2.jar is an implementation for 
JainSipApi1.1.jar  TOO!

Question 1)
so I will like to understand one thing, is the exactly same codebase in 
nist-sip-1.2.jar implementing for both JainSipApi1.2.jar  & 
JainSipApi1.1.jar  ?? any versioning problem here?

Question 2)
is my understanding correct?
NIST-SIP1.2 implements JAIN-SIP1.2
NIST-SIP1.2 implements JAIN-SIP1.1
NIST-SIP1.1 implements JAIN-SIP1.0

Question 3)
in jcp.org JSR-32 website, there is nothing to mention JAIN-SIP1.2  . I 
am very confused.
is JAIN-SIP1.2  just a minor fix to JAIN-SIP1.1 ? any list of change log?

Regards,
Manchi