Simply you can't. You should use BURG for it. The only thing you can do is, changing GRUB's background with the themes' one. But you can't get OS icons etc. on GRUB.
BURG's theme syntax is very similar to GRUB2's (because BURG's theme engine is a fork of GRUB2's). Ports of many popular BURG themes are available in this tar.gz: jordanu.dyndns.org/grub/themes.tgz and two themes created specifically for GRUB2 are available here: http://apebox.org/wordpress/linux/261/ .
Simply you can't. You should use BURG for it. The only thing you can do is, changing GRUB's background with the themes' one. But you can't get OS icons etc. on GRUB.
BURG's theme syntax is very similar to GRUB2's (because BURG's theme engine is a fork of GRUB2's). Ports of many popular BURG themes are available in this tar.gz: jordanu.dyndns.org/grub/themes.tgz and two themes created specifically for GRUB2 are available here: http://apebox.org/wordpress/linux/261/ .