Hi Sahil,
If you want to use solution manager SLD as central SLD then you have to setup SLD bridge as you must be having PI SLD in your landscape.
Also, setup local SLD in Solman as told before. Once the SLD bridge is setup, all system registered in PI SLD will come in Solman SLD and system which tre not registed in PI SLD can be registered directly to your solman SLD.
To setup forwarding, goto you PI SLD and add Solman SLD
Choose administration -> data suppliers and click the Add SLD button.
Enter the appropriate input values:
Under URL, enter http://<solmanhost>:5<instanzce number>00.
Under User, enter the SLDDSUSER.
Under Password, enter the password of the SLDDSUSER.
Divyanshu