Hi Jennifer,
Tapa can be very brittle and has a lot of paper qualities.  If you haven't humidified paper before, please consult a local conservator.
With that in mind, here are my thoughts:
You might try to humidify the tapa cloth in a chamber first before trying to open it in order to prevent cracking along the creases.  You can try a cold poultice or Goretex humidification once it is opened.  The thing to remember is to do this slowly; the creases may return if not allowed to humidify and return to the ambient environment slowly.  For stubborn creases, you might try an ultrasonic humidifier that has a "pen-tip" nozzle to aim the vapor at the creases.  I don't recommend steaming.
There are many options for display, and I know this will sound a bit silly, but I like magnets.  Lee Valley sells rare earth magnets which can be covered with Japanese tissue paper, painted to blend in with the tapa cloth and be invisible.
There is a great Archetype publication, edited by Margot M.Wright that has several articles on the storage, conservation and display of Barkcloth (called Barkcloth).

Beth Szuhay
Textile Conservation
Fine Arts Museums of San Francisco  
> ----------
> From:         Textile Conservators on behalf of Jennifer Feik
> Reply To:     Textile Conservators
> Sent:         Thursday, August 4, 2005 9:53 AM
> To:   [log in to unmask]
> Subject:      tapa cloth
> 
> Hello,
>  
>    I have a Polynesian tapa cloth that has been folded in a box for years that my curators now want to put on display.  I have read that after testing the color fastness a steamer can be used to remove creases.  Is this the best option?  I am also interested in the best way to hang the tapa.  Normally with textiles I would carefully stitch it to a backing that could be stitched or velcroed to a slant board, but I don't want to introduce holes into the tapa.  Do you know of any better methods for hanging a tapa cloth?  The exhibit is intended to be permanent, but I'm not sure if that is a good idea for tapa cloth.  
>  
> Thank you for your help!
>  
> Jennifer Hadley
> Associate Registrar
> Museum of Church History and Art
> 
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