ESOP Added In CTC Structure But Not Reflected On Offer Letter

I have been offered a job and the HR sent me a salary structure for acceptance with total CTC which includes ESOP( which I have to buy at base price usually lesser), however the same is not reflected in the offer letter salary details?
I am bit concerned with this move of HR, please provide your valuable suggestions on how to proceed further.

It's the most fool making funda used now a days in some reputed industries.Before joining plz clarify following:
1. IS there any service time bond is attached with it?
2. How to encash it & eligibility to encash it?
3. Do I have to submit the securities for it?
4. If I dont prefer it than how will you pay the same to me.
Rg/
Sanjay

ESOP - Employees Stock Option Plan.
ESOPs are being used to retain the ppl for a min period of 2 yrs or more with lot of strings attached. Lock-in period is also there. Better get the confirmation from the HR before making any move.
Pon