I want to copy a protected sheet.. and keep it protected?!?

hi all
I have a worksheet I use to balance a cash register in a little retail store. We have a point of sale register but we use excell to double check all the figures and provide a running record for accounting purposes.
Each day we use a template worksheet which has a number of calculations set up to add up the takings in cash, credit cards etc.
There are a number of unprotected cells, where we can enter numbers for the amounts taken in various transactions, and then a number of cells with calculations set up to work with this data.
I want to protect the calculation cells so they cannot be overwritten by accident as we enter the daily data in. I have protected these cells by by selecting them, and checking the 'protect cells' checkbox in the format cells dialog, and then protecting the sheet via the tools menu.
BUT!
at the end of each day I want to copy the worksheet and reset the editable values so we can do it all again the next day. I do this by right clicking on the sheet tab at the bottom of the screen, picking move or copy, ticking the 'create a copy' checkbox, and renaming the resulting duplicate worksheet.
however when I do this I find that my new worksheet is NO LONGER PROTECTED. I have to go back to tools>protection>protect worksheet and add a new password.
Is there a way I can duplicate my sheet and retain these protection settings?
I'm reasonably savvy with excell but I've been trying to work this out for a while and it is beyond me. If there are any clever nerds out there who can help me I would REALLY appreciate it!

thanks in advance

dan

thanks for the responses guys! awesome.
I couldn't get nathansavs code to work - this is probably my inexperience with vba macros...
TMS's second option works well in a very simple test spreadsheet with two data cells and a locked calc cell (adding the 2 data cells together) - but when I try it in a version of my actual .xlsb i get a Run-time error '9': Subscript out of range...?
When I debug the code this line is highlighted:
Set ws = Sheets("Sheet1")
could this be because we name each tab with the day and date? Sorry if this makes things more complicated!
what would be truly awesome is if there was a way we could add to the code to prompt a dialog box asking the user to name the new duplicate worksheet! too hard?

love to hear your helpful thoughts!
thanks again

dan

Originally Posted by dan_native

I want to protect the calculation cells so they cannot be overwritten by accident as we enter the daily data in. I have protected these cells by by selecting them, and checking the 'protect cells' checkbox in the format cells dialog, and then protecting the sheet via the tools menu.

Sounds to me like you don't really need to use Protect Cells.

You can spoof the same effect with Data Validation: just set it to throw up a warning anytime the user tries to input over the existing fomula.

Data Validation carries over when the tab is copied, so there's no need for a VBA solution.