merge two workfiles with different period

[omss]

Dear Sir,
I have two workfiles, the first with series from 1965m1 to 2015m3, the second with the same series from 1965m1 to 2015m2. I want to keep the same values series in the second workfile from 1965m1 to 2004m12 and copy the first workfile news values series from 2005m1 to 2015m3 in the second workfile but when i merge these workfiles the program only write the last new value and keep the other same value from 1965m1 to 2015m2.

I tried with this program :
copy(m,smpl=2005m1 {lastmonth}) workfile1::extrac{!i}\* workfile2::workfile2\

but this program doesn't change values from 2005m1 to 2015m2, it only write the mast value 2015m3 from worfile1 in worfile2

Can you help me?
Thanks very much

PS : sorry for my english, i am french :-)

[EViews Gareth]

There isn't a way to do that in one go. I would copy it a to a new series with a different name, then set the sample to be 2005 onwards, and set the first series equal to the second.