SQL queries on date fields

Hi,

We are using a linked server to query some Cobol data files through AcuXDBC on a new server. 

A query looked like this on the old server: select * into _t1 from openquery(XDBC_TESTREM,'select  * from gjen'). It was working well. However, after we switched to the new server I started getting some errors and I had to format the date columns like this:

CONVERT(NVL(CONVERT(GJ_DEPOTDATO,SQL_CHAR),TO_DATE(719527,''YYYYMMDD'')),SQL_DATE) AS GJ_DEPOTDATO

I have 3 questions:

1. What can I do to avoid using that convert statement? Is there any setting somewhere that can make this work by default? (otherwise I will have to change all the queries)

2. Some dates are like this: 5112012. They are missing a leading zero. I tried a CASE WHEN char_length(...) = 7 THEN.. but I get an error saying that function 30 is not implemented yet. How can I handle this type of dates? (i am thinking to return them as SQL_CHAR and convert them in t-sql to dates)

3. Where can I find a full list of supported SQL syntax?