Please read
http://docs.mantisbt.org/master/en/administration_guide.html#ADMIN.CUSTOMIZE.STATUS

I have tried both the options from below links.But status entry is not listed.

1. http://docs.mantisbt.org/master/en/administration_guide.html#ADMIN.CUSTOMIZE.STATUS [^]

2. http://www.mantisbt.org/manual/manual.customizing.mantis.customizing.status.values.php

If you still use MantisBT 1.2.0 you should update to version 1.2.8
I am not able to reproduce the issue using latest stable version of MantisBT.
Please provide step by step instructions to reproduce the issue.

I did upgrade it to 1.2.8 version and tried the similar settings on the latest version. But the result is same.

@Atrol, did I miss anything apart from what was mentioned in both the posts?

Add the following files as attachments:
config_inc.php (remove your database password)
custom_strings_inc.php
custom_constants_inc.php
A screenshot of page: Manage -> Manage configuration -> Workflow Transitions

I was able make them listed, through MANAGE WORKFLOW Section.

Seems like there is a blocking issue to use these fields any further. Please check the attached images

1.Status Entries Listed.png
2.Blocking Issue.png
3.Workflow.png

Following entries marked with * are my new entries as a STATUS fields.

new
feedback
acknowledged
confirmed
assigned
Code-Review-Assignment-PENDING
Code-Review-INPROGRESS
Code-Review-Phase-PASSED
Code-Review-Phase-FAILED
Verified
Needs-Onsite-Verifiaction
resolved
closed

Normally when a bug is assigned and if the Developer-1 corrects the piece of code, he will be entitled to update the status to "Code-Review-Assignment-PENDING"

Project Lead will filter out the issues with the status "Code-Review-Assignment-PENDING" and assigns back to Developer-2 [other than the one who fixed it] for carrying out the Code Review and also sets the status to "Code-Review-INPROGRESS"

Developer-2 after carrying out the code review shall be entitled to update the status to either "Code-Review-Phase-PASSED" or "Code-Review-Phase-FAILED"

The testers are required to filter out the issues with status "Code-Review-Phase-PASSED" and should proceed for next phase of resolving the issue status accordingly. The further course of action and workflow from here on shall remain same as before

Also attached config files for your reference.

I am getting APPLICATION WARNING when accessed with the newly defined custom fields.

Sample Error is as follows.

APPLICATION WARNING #300: String "CORRECTED-Code-Review-Assignment-PENDING_bug_title" not found.

You set 6 times the same strings in custom_strings_inc.php

$s_to_be_tested_bug_button = "CORRECTED-Code-Review-Assignment-PENDING";
$s_to_be_tested_bug_title = "Set CORRECTED-Code-Review-Assignment-PENDING";
$s_email_notification_title_for_status_bug_to_be_tested = "The following issue is Corrected & Pending with Code Review.";

you have to set the 3 strings for every status you defined

$s_CORRECTED-Code-Review-Assignment-PENDING_bug_button
$s_CORRECTED-Code-Review-Assignment-PENDING_bug_title
$s_email_notification_title_for_CORRECTED-Code-Review-Assignment-PENDING

spacomp, as this is not a bug or feature request for MantisBT (you are asking for help on how to configure MantisBT) I am resolving this issue as "no change required".
Please use the forums, the help mailing list or IRC to get support on customising and using MantisBT.
http://www.mantisbt.org/support.php

@spacomp, please note that '-' is not a valid character for a PHP keyword. This is likely what is causing the error you're seeing. Use '_' instead.

There are also errors in your workflow definitions in config_inc.php, the transitions for a given status, should not include the same, i.e.
$g_status_enum_workflow[RESOLVED] = '50:assigned,90:closed';
NOT $g_status_enum_workflow[RESOLVED] = '50:assigned,80:resolved,90:closed';

It's probably easier to let Mantis manage these definitions for you by using the manage_config_workflow_page.php

Finally got a Solution :).

Thank you very much Atrol, Dregad.