SLC: how to realize alias logon that supplier created after registration approved?

Hi, everyone

   I am implementing  SLC.  After supplier's registration approved,  the system sent two mails to supplier contact,  one is for user ID  like 'PKVCVYVNFTXZ',  one is for password.

   Supplier gets the URL from mail as bellow:

http://<hostname>:<port>/sap/bc/bsp/srmsmc/ros_ext_2/ros_bsp_second.do?sap-client=200&sap-user=PKVCVYVNFTXZ

  Supplier enters the URL and creates a user name like 'V0001' that is actually the alias of 'PKVCVYVNFTXZ'.

The next step.  supplier will logon on URL: 'http://<hostname>:<port>/sap/bc/bsp/srmsmc/s3q_ext/default.htm?sap-client=200'  by alias 'V0001'.

my question: how to access the URL by alias ,  what setting will be do ?

thanks!

Jesse