From Forum Nokia Wiki

This tool is used for requesting a Developer certificate from www.symbiansigned.com. It asks for details about the certificate to be created, then produces a *.csr file which can be uploaded to the Symbian Signed website to request the certificate.

It can be downloaded from here: Symbian DevCert Request Tool for Windows, either as a stand-alone application, or as a plugin for Carbide.c++.

Installing the plugin version for Carbide

As the instructions for installing the plugin on the Symbian site are a bit vague, here is a list of steps that should work:

1. Download the "DevCert Request Plugin for Eclipse" from here.
2. Extract the .zip file with directories to a temporary folder
3. Copy the contents of the dev\ subdirectory (that is, the folders named com.symbian.devservices.devcertrequest_1.0.5 etc.) to \Program Files\Nokia\Carbide.c++ v1.2\plugins (or wherever your Carbide installation lives)
4. Restart Carbide - after this, a Tools menu should appear that contains nothing but the "Symbian Signed" submenu, where you will find the new tool.

If the plug-in does not appear when you restart Carbide.c++, close Carbide.c++ and restart it from the command line using the clean switch (e.g. carbide.c++.exe -clean). This resets the plug-in information in Carbide.c++ and you should now see the plug-in as described above.