The wiki and sample codecs wer a great help to understand how mining works and how the succeesful work is upload.

Following things I understand:

• ne blocks are headers of 80 Bytes with hash bewol difficulty
• the work is sent to port 8332 via json to minerd
• the only free chosable field is nonce
• the data is changed on every transaction, and timestamp

But i need to answer some questions. Is my succesful work invalid, if a new transaction occurs or the timestamp changes, just before i have the data uploaded? Sometimes it may be quite impossible to break the difficulty, because 2^32 nonce values are very little amount against 2^256 bit hash length (have to be zero).