how to convert a string array to a string. fct array_to_string seem to work only for INT array??

Hi all,

  I'm messing with this, I think simple, problem.  I searched the doc
and the web without success .. hum
I have a string array(Compte[]) and I need to create the following
string statement to populate a temporary table

statement := ' INSERT INTO T_CR1 ( CRNUM, CRMONT, CSGLNUM, CRDATE)
                    SELECT CRNUM, CSGLNUM, CRMONT, CRDATE
                    FROM CR INNER JOIN CS ON CR.CRNUM = CS.CSCRNUM AND
CR.CRYPNUM = CS.CSYPNUM
                    WHERE CRYPNUM = ' || quote_literal(companyId) || '
                         AND CRDATE  <= CURRENT_DATE
             AND CSGLNUM IN {'  || array_to_string(Compte, ',') || '}';

    EXECUTE statement;

For now I get :

 INSERT INTO T_CR1 ( CRNUM, CRMONT, CSGLNUM, CRDATE)
                    SELECT CRNUM, CSGLNUM, CRMONT, CRDATE
                    FROM CR INNER JOIN CS ON CR.CRNUM = CS.CSCRNUM AND
CR.CRYPNUM = CS.CSYPNUM
                    WHERE CRYPNUM = 'M'
                         AND CRDATE  <= CURRENT_DATE
             AND CSGLNUM IN {cpt1, cpt2}


But I want:

 INSERT INTO T_CR1 ( CRNUM, CRMONT, CSGLNUM, CRDATE)
                    SELECT CRNUM, CSGLNUM, CRMONT, CRDATE
                    FROM CR INNER JOIN CS ON CR.CRNUM = CS.CSCRNUM AND
CR.CRYPNUM = CS.CSYPNUM
                    WHERE CRYPNUM = 'M'
                         AND CRDATE  <= CURRENT_DATE
             AND CSGLNUM IN {'cpt1', 'cpt2'}

How can I do that.  I expected to find a standard function in the doc to
do that ...

Thanks for your help!

Best Regards
David