Using NAnt RC4 to build .Net 1.1 Code

Hi

I am in a conversion project of Code from .Net 1.1 -->.Net 2.0 .

1. I am going to build all my projects with NAnt RC4 version and also with
VS2005 to check the affected Areas.
2. I have both the Versions of my code in my machine, 1.1 and 2.0.
3. My requirement is to use NAnt RC4 version for building both my 1.1 and
2.0 code ad RC4 supports both.
4. I am able to Build both the 1.1 and 2.0 code with NAnt RC4.

Here is my problem and Question:

1. when i build my 2.0 code with RC4 its perfect.
2. When i build my 1.1 code with RC4 i get messages like ..'Method is
deprecated..and so ' these messages are obtained for my .Net Framework 1.1
code...

why is NAnt RC4 --when building my 1.1 getting me these '...Deprecated...'??

As Nant RC4 supports both 1.1 and 2.0 , how can i get rid of the
'..Deprecated methods..'?

Should i do any settings do get rid of these messages when i build 1.1 with
RC4 ?

Please let me know on this ...
Thanks
Senthil

SenthilVel