User Copy User incl. Passwords as hash

Hello,

we have to copy all existing users from one UME system to another including the passwords.

I have tried to use the java UME interface, which allows me to read the j_password as a hash value e.g.

String pwd = userAccountSystem1.getAttribute("com.sap.security.core.usermanagement", "j_password" )[0];

which returns me an hash value like

{SSHA}FzQ4Cw3g0qD0/3SRyeaDVKSONIp0aeS8nlA=

but whenever i try to set this hash value within the new UME system using the same interface like

userAccountSystem2.setAttribute( "com.sap.security.core.usermanagement", "j_password", new String[]{pwd} );

then this actually does not really work. If I try to re-read the just set value, then the returned value is

{SSHA}rUR/RNgKMXbDH0Scgy+hkEZWZiF1waVJLdQ=

Is there somehow a way to set the hash code using the UME java interface?

Any recommendation how users can be copied including the passwords (just the hash codes, not the readable password)

Thank you for your help,

Andreas