How to give custom redirect url in request token


Hi all
I have problem with Twitter Authentication,
Step 1:
I have given the request token url as below,
base_url1 = “{oauth_consumer_key}&oauth_token=&oauth_nonce=#{oauth_nonce}&oauth_signature_method=HMAC-SHA1&oauth_timestamp=#{oauth_timestamp}&oauth_version=1.0&oauth_signature=#{signa}

Step 2:
and, authorize url as
first = “{@oauth_token}

I am getting the request token,secret value and oauth verifier value from this,

But i need to redirect to a custom url as
call_back_url = “{System.get_property(‘rhodes_port’)}#{url_for(:action => :fb_initiate_callback)}”

I dono how to give this callback url with request token url…
If i give &oauth_callback=#{call_back_url} with the step 1— it does not generating the token, it passing nil oauth_token and secret value.

Can anybody help me , to complete this authentication with custom callback url…