That's so hard to request customer to purchase additional VS2010's license.
you can install trial version of VS2010 for 90 days and extend it for another 30 days if there is a need,so an develop all of your reports.
After my try, VS2012 shell can past the validataion during installation, but it seems it cannot be used for development. Any other options?
Thanks for your suggestion. I will consider it as backup option.