H1 transfer without client letter

[thunderboltns]

Hi All

I am in 6th year of my H1B with company A, and its expiring in another 5 months (Jul 2012), I have my I-140 approved.
Company B filed my PERM as future employment, now I am thinking to transfer my H1 to company B.
Current client is not ready to give client letter, but I can get the letter from Prime vendor and submit all other documents like
timesheets, security batch etc.

Some people are saying client letter is must for H1 transfer.

Has anyone transferred H1 without client letter? Please share your experience.


Thanks

[skal]

Preferred Vendor letter works in place of Client Letter for transfers/extensions.