This is a little bit complicated. You can use the following script (tested on SAP Rel 4.6C). It copies the English sales text into the GuiXT text "t1".

// InputScript to read the English sales text in MM03(SAP 4.6C)

  Enter "=SP08"    

  // set organisation data in popup (test data IDES)

Screen SAPLMGMM.0081

  Set F[Plant]    "1000"

  Set F[Sales org.]     "1000"

  Set F[Distr. channel]       "10"

  Enter

label salestextscreen  

Screen saplmgmm.4040

CopyText fromScreen="X[LONGTEXT_VERTRIEBS]" toText="t2"

 // Check language (title of text)

Set V[MM03_salestext_language] "&F[LONGTEXT_MAINTAINED_TEXT]"

if V[MM03_salestext_language=Englisch]

   Enter "=SP01"  // OK, back to Basic data 1

   Leave  

endif

// Search matching language in table

// Language is in 2nd column

Set V[i] 1

Label l1

  Set V[MM03_salestext_language] "&cell[Gepflegte Languagen,2,&V[i]]"

  // Language found? then select it

  if V[MM03_salestext_language=English]

    Enter "=TLAN0&V[i]"    // max. 9 languages           

    goto salestextscreen

  endif

  // end of language table?

  if not V[MM03_salestext_language]

    Enter "=SP01"  

    Leave 

  endif

  // next language

  Set V[i] &V[i] + 1

  goto l1