But when i enter BTC amount it occur "not enough fund" even if i try to send a much smaller amount including Fees
It can happen if you have 0 HEAT, because you need at least 0.01 HEAT for any transaction including a BTC asset withdrawal transaction
until someone manualy send real BTC to my acc?, reminds me of NXT AE with multigateways except its not a full automatic process, controled by heat audits?
Correct. Manual audit is a temporary solution to enable usage of the Heatwallet BTC gateway during this time while full automation / decentralisation is still under development.