Fulltime to client

[Vishnu103]

Currently, I am on OPT. And I was working for a client "C" for morethan a year, through Vendor "V" through my employer E1(Indian). Recently, H-1B get picked in the random selection process and got RFE through other employer E2(Indian). E2 asked me to come on his company payroll before answering RFE. Then, I spoke to E1 to make a subcontract with E2. Initially E1 asked me for 20% to do subcontract. Later he agrred for 15%. My main intension at that time is to get H-1B approval. So i aggred with E1. 
Now, My client is offering me fulltime job to work for them(Once H-1B activated,start date in late october). There is no problem for vendor V and current employer E2 to go for fulltime to client. But with my old employer E1, I have signed NDA(Non disclosure agreement), saying that i can not work client directly or indirectly till 12 months from the end of contract. And now,i do not have a good relationship with E1. E1 is not allowing me to go for Fulltime.
If i accept the full time offer from client. There is threat from my old Employer E1. So How can i handle my old employer E1.? Please provide any suggestions or share your experience.

[bhaigan]

Since E1 knows you are going to fte he will hold your pay for some months, he will threaten for 20 to 40 k before moving to full time. So risk is at your side. If he holds your pay just leave it and go to full time