Hi,
Regarding other IDE besides the CodeWarrior classic you may consider IDE's listed at product page:http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=S12XHY&fpsp=1&tab=Design_Tools_Tab
under section
IDE - Debug, Compile and Build Tools
You have the option of:
by COSMIC
package includes an integrated IDE, optimizing ANSI C compiler for S12(X)and XGATE co-processor, real-time target debugger & flash programmer,...
or
by IAR
IAR Embedded Workbench for HCS12 is an integrated development environment with project management tools and editor. It includes a highly optimizing...
or
by ISYSTEMAG
winIDEA is an integrated development environment (IDE) that compliments all iSYSTEM hardware. - Editor, project and build manager, high level...
CW5.1 for S12XHY doesn’t have full chip simulation feature for full debugger support.
You can enable it but it can be used only for simulating instruction.
This is the method:
Press F5 to launch debugger, in connection manager, hit “Abort”:

Then launch debugger, go to debugger menu “ component”, “Set connection…”, choose “full chip simulation”

Then go to debugger menu “File”, “Save Configurations”.
Close CW debugger.
Next time launch debugger again, it will run in full chip simulation mode. please note, this is a kind of Instruction Set Simulator. Unfortunately you can’t utilize all the S12XHY features with it.
In CodeWarrior 10.6 S12XHY is not implemented nor supported.