As far as I know all brokers will accept offshore companies as clients as long as you supply them with the paperwork they require.
They may require acceptable I.D. of the trader (photo id, eg... passport), the company (Memorandum of articles etc), proof of residence of the trader and the company (Utility bill with traders name and same for the company) and proof of banking account.
There may be other requirements but I believe these are the main ones.
In the days of old when sailors were bold, and seldom if ever contented.