SSIS - Timestamp Issue

Hello

I have timestamp in my SSIS Package. I have variable - String Data type and i have put below expression.

Expression for Variable: RIGHT("0" + (DT_STR,2,1252)DATEPART("MM" ,GETDATE()), 2) + RIGHT("0" + (DT_STR,2,1252)DATEPART("DD" ,GETDATE()), 2) +  (DT_STR,4,1252)DATEPART("YYYY" ,GETDATE())  + "_"
+ Right("0" + (DT_STR,4,1252) DatePart("hh",getdate()),2) + "" + Right("0" + (DT_STR,4,1252) DatePart("n",getdate()),2)  +""+ Right("0" + (DT_STR,4,1252) DatePart("ss",getdate()),2)

So Now i am using this variable for Filename. There are three tasks, where this variable has been used.

First task creates txt file and use this variable to put filename.

Second task creates encrypted file and use this variable to put filename

Third task - FTP task which takes encrypted file and put it on FTP site

Third task fails, because encrypted file name will be abc_12050212_063003 and when FPT Task will run, it will look for abc_12052012_063004

Because variable value will be keep changing. Can I keep static value for timestamp variable for whole package?

Please help

Thanks