Only works 80% the rest like those send & receive blocks have to be manually set up. There is windows Step5 software to help a little but it is going to be some hard work ahead. The siemens S7 software does not work 100%. This is a good question for the forum.
I have changed a program and ended up almost rewriting the program.
Have you googled this. http://www.softwaretoolbox.com/store/item_pages/itempage_510.asp
One pitfall is if you intend to reuse the SINEC-L2.
Are there SINEC-L2 slaves attached to the IM308 ?
If so, you must be aware the initial variant of SINEC-L2 is not compatible with Profibus DP. A later variant was called SINEC-L2 DP, and it was compatible with Profibus DP.