sale to SEZ is to be treated as zero retad supllies and shall be treatment as deemed exports and shall be given the same treatment as Exports.If you are a registered taxable person exporting goods or services, you can do so under the two categories as under :
a. Export under bond or letter of undertaking without payment of Integrated Tax (IGST) and claim refund of unutilized input tax credit.
b. Export on payment of Integrated Tax and claim refund of the tax (IGST)so paid on Exports / Deemed Exports . please do mention on the invoice as to under which category are you exporting / selling to SEZ
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